bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating Meiotic Exchange Patterns From Recombination Data: An Application to Humans
Authors: Lamb Neil E , Feingold Eleanor , Sherman Stephanie L
Published: January 2021

We present analytical methods to estimate the recombinational history of chromosomes in a human population. Our analysis, similar to those utilized in Drosophila, can be used to construct meiotic maps based upon crossover frequencies observed in family data. We apply this method of exchange estimation to a population of paternally and maternally inherited chromosomes 21. The patterns of chromosomal exchange estimated by this type of analysis are comparable to those obtained by the more technically difficult method of cytologically counting chiasmata among human male meiotic events (sperm). This type of analysis can be applied to both male and female meiosis, circumventing many technical problems inherent to cytological counting. Moreover, the distribution of exchange locations along a chromosome for each exchange type (i.e., single, double, or triple exchanges) can be examined individually, an advantage compared to examination of genetic maps that only provide a summary of these distributions. We discuss how this analysis can be used to examine various assumptions concerning meiotic exchange in humans and investigate properties of the analysis that contribute to the accuracy of the results.
Mating Type in Chlamydomonas Is Specified by mid, the Minus-Dominance Gene
Authors: Ferris Patrick J , Goodenough Ursula W
Published: January 2021

Diploid cells of Chlamydomonas reinhardtii that are heterozygous at the mating-type locus (mt  +/mt  –) differentiate as minus gametes, a phenomenon known as minus dominance. We report the cloning and characterization of a gene that is necessary and sufficient to exert this minus dominance over the plus differentiation program. The gene, called mid, is located in the rearranged (R) domain of the mt  – locus, and has duplicated and transposed to an autosome in a laboratory strain. The imp11 mt  – mutant, which differentiates as a fusion-incompetent plus gamete, carries a point mutation in mid. Like the fus1 gene in the mt  + locus, mid displays low codon bias compared with other nuclear genes. The mid sequence carries a putative leucine zipper motif, suggesting that it functions as a transcription factor to switch on the minus program and switch off the plus program of gametic differentiation. This is the first sex-determination gene to be characterized in a green organism.
Involvement of the Yeast DNA Polymerase δ in DNA Repair in Vivo
Authors: Giot Loïc , Chanet Roland , Simon Michel , Facca Céline , Faye Gérard
Published: January 2021

The POL3 encoded catalytic subunit of DNA polymerase δ possesses a highly conserved C-terminal cysteine-rich domain in Saccharomyces cerevisiae. Mutations in some of its cysteine codons display a lethal phenotype, which demonstrates an essential function of this domain. The thermosensitive mutant pol3-13, in which a serine replaces a cysteine of this domain, exhibits a range of defects in DNA repair, such as hypersensitivity to different DNA-damaging agents and deficiency for induced mutagenesis and for recombination. These phenotypes are observed at 24°, a temperature at which DNA replication is almost normal; this differentiates the functions of POL3 in DNA repair and DNA replication. Since spontaneous mutagenesis and spontaneous recombination are efficient in pol3-13, we propose that POL3 plays an important role in DNA repair after irradiation, particularly in the error-prone and recombinational pathways. Extragenic suppressors of pol3-13 are allelic to sdp5-1, previously identified as an extragenic suppressor of pol3-11. SDP5, which is identical to HYS2, encodes a protein homologous to the p50 subunit of bovine and human DNA polymerase δ. SDP5 is most probably the p55 subunit of Polδ of S. cerevisiae and seems to be associated with the catalytic subunit for both DNA replication and DNA repair.
Evidence for an Inducible Repair-Recombination System in the Female Germ Line of Drosophila melanogaster. III. Correlation Between Reactivity Levels, Crossover Frequency and Repair Efficiency
Authors: Laurençon Anne , Gay Françoise , Ducau Judith , Bregliano Jean-Claude
Published: January 2021

We previously reported evidence that the so-called reactivity level, a peculiar cellular state of oocytes that regulates the frequency of transposition of I factor, a LINE element-like retrotransposon, might be one manifestation of a DNA repair system. In this article, we report data showing that the reactivity level is correlated with the frequency of crossing over, at least on the X chromosome and on the pericentromeric region of the third chromosome. Moreover, a check for X-chromosome losses and recessive lethals produced after gamma irradiation in flies with different reactivity levels, but common genetic backgrounds, brings more precise evidence for the relationship between reactivity levels and DNA repair. Those results support the existence of a repair-recombination system whose efficiency is modulated by endogenous and environmental factors. The implications of this biological system in connecting genomic variability and environment may shed new lights on adaptative mechanisms. We propose to call it VAMOS for variability modulation system.
Discordant Rates of Chromosome Evolution in the Drosophila virilis Species Group
Authors: Vieira Jorge , Vieira Cristina P , Hartl Daniel L , Lozovskaya Elena R
Published: January 2021

In Drosophila, the availability of polytene chromosome maps and of sets of probes covering most regions of the chromosomes allows a direct comparison of the organization of the genome in different species. In this work, we report the localization, in Drosophila virilis, D. montana, and D. novamexicana, of >100 bacteriophage P1 clones containing ~65 kilobase inserts of genomic DNA from D. virilis. Each clone hybridizes with a single euchromatic site in either chromosome 1 or chromosome 3 in D. virilis. From these data, it is possible to estimate the minimum number of inversions required to transform the map positions of the probes in one species into the map positions of the same probes in a related species. The data indicate that, in the D. virilis species group, the X chromosome has up to four times the number of inversions as are observed in chromosome 3. The first photographic polytene chromosome maps for D. montana and D. novamexicana are also presented.
The Genes raw and ribbon Are Required for Proper Shape of Tubular Epithelial Tissues in Drosophila
Authors: Jack Joseph , Myette Guy
Published: January 2021

The products of two genes, raw and ribbon (rib), are required for the proper morphogenesis of a variety of tissues. Malpighian tubules mutant for raw or rib are wider and shorter than normal tubules, which are only two cells in circumference when they are fully formed. The mutations alter the shape of the tubules beginning early in their formation and block cell rearrangement late in development, which normally lengthens and narrows the tubes. Mutations of both genes affect a number of other tissues as well. Both genes are required for dorsal closure and retraction of the CNS during embryonic development. In addition, rib mutations block head involution, and broaden and shorten other tubular epithelia (salivary glands, tracheae, and hindgut) in much same manner as they alter the shape of the Malpighian tubules. In tissues in which the shape of cells can be observed readily, rib mutations alter cell shape, which probably causes the change in shape of the organs that are affected. In double mutants raw enhances the phenotypes of all the tissues that are affected by rib but unaffected by raw alone, indicating that raw is also active in these tissues.
Mutation-Selection Balance Under Genomic Imprinting at an Autosomal Locus
Authors: Spencer Hamish G
Published: January 2021

I model the effect of genomic imprinting on the equilibrium allele frequencies at an autosomal diallelic locus subject to viability selection and mutation. The population size is assumed to be very large; male and female mutation rates may be unequal. Different models examine cases of the inactivation of one gene (with both complete and partial penetrance) and of differential expression of genes according to the parent of origin. In the simplest cases the frequency of the deleterious allele is approximately twice that of a dominant nonimprinting mutant, but considerably less than that of a recessive nonimprinting mutant. Under imprinting, selection and unequal mutation rates interact: other things being equal, male-biased mutation leads to lower mutant frequencies under maternal imprinting and higher frequencies under paternal imprinting. I also model cases where just one allele is imprintable (and the other not). These models allow us to predict the frequency of a failure to imprint in a normally imprinting system, as well as the frequency of imprinting at a standard nonimprinting locus.
Balancing Selection on Electrophoretic Variation of Phosphoglucose Isomerase in Two Species of Field Cricket: Gryllus veletis and G. pennsylvanicus
Authors: Katz Laura A , Harrison Richard G
Published: January 2021

Two species of crickets, Gryllus veletis and G. pennsylvanicus, share six electrophoretic mobility classes for the enzyme phosphoglucose isomerase (PGI), despite evidence from other genetic markers that the two species are not closely related within eastern North American field crickets. Moreover, the frequencies of the two most common PGI electrophoretic classes (PGI-100 and PGI-65) covary in sympatric populations of these species in the eastern United States, suggesting that PGI may be subject to trans-specific balancing selection. To determine the molecular basis of the electrophoretic variation, we characterized the DNA sequence of the Pgi gene from 29 crickets (15 G. veletis and 14 G. pennsylvanicus). Amino acid substitutions that distinguish the electrophoretic classes are not the same in the two species, and there is no evidence that specific replacement substitutions represent trans-specific polymorphism. In particular, the amino acids that diagnose the PGI-65 allele relative to the PGI-100 allele differ both between G. veletis and G. pennsylvanicus and within G. pennsylvanicus. The heterogeneity among electrophoretic classes that covary in sympatric populations coupled with analysis of patterns of nucleotide variation suggest that Pgi is not evolving neutrally. Instead, the data are consistent with balancing selection operating on an emergent property of the PGI protein.
Splice-Junction Elements and Intronic Sequences Regulate Alternative Splicing of the Drosophila Myosin Heavy Chain Gene Transcript
Authors: Standiford David M , Davis Mary Beth , Sun Weitao , Emerson Charles P
Published: January 2021

The Drosophila muscle myosin heavy chain (Mhc) gene primary transcript contains five alternatively spliced exon groups (exons 3, 7, 9, 11 and 15), each of which contains two to five mutually exclusive members. Individual muscles typically select a specific alternative exon from each group for incorporation into the processed message. We report here on the cis-regulatory mechanisms that direct the processing of alternative exons in Mhc exon 11 in individual muscles using transgenic reporter constructs, RT-PCR and directed mutagenesis. The 6.0-kilobase exon 11 domain is sufficient to direct the correct processing of exon 11 alternatives, demonstrating that the alternative splicing cis-regulatory elements are local to Mhc exon 11. Mutational analysis of Mhc exon 11 reveals that the alternative exon nonconsensus 5′-splice donors are essential for alternative splicing regulation in general, but do not specify alternative exons for inclusion in individual muscles. Rather, we show, through exon substitutions and deletion analyses, that a 360-nucleotide intronic domain precisely directs the normal processing of one exon, Mhc exon 11e, in the indirect flight muscle. These and other data indicate that alternative exons are regulated in appropriate muscles through interactions between intronic alternative splice-specificity elements, nonconsensus exon 11 splice donors and, likely, novel exon-specific alternative splicing factors.
An Approximate Model of Polygenic Inheritance
Authors: Lange Kenneth
Published: January 2021

The finite polygenic model approximates polygenic inheritance by postulating that a quantitative trait is determined by n independent, additive loci. The 3n possible genotypes for each person in this model limit its applicability. Cannings, Thompson, and Skolnick suggested a simplified, nongenetic version of the model involving only 2n + 1 genotypes per person. This article shows that this hypergeometric polygenic model also approximates polygenic inheritance well. In particular, for noninbred pedigrees, trait means, variances, covariances, and marginal distributions match those of the ordinary finite polygenic model. Furthermore as n → ∞, the trait values within a pedigree collectively tend toward multivariate normality. The implications of these results for likelihood evaluation under the polygenic threshold and mixed models of inheritance are discussed. Finally, a simple numerical example illustrates the application of the hypergeometric polygenic model to risk prediction under the polygenic threshold model.
An Empirical Evaluation of Genetic Distance Statistics Using Microsatellite Data From Bear (Ursidae) Populations
Authors: Paetkau David , Waits Lisette P , Clarkson Peter L , Craighead Lance , Strobeck Curtis
Published: January 2021

A large microsatellite data set from three species of bear (Ursidae) was used to empirically test the performance of six genetic distance measures in resolving relationships at a variety of scales ranging from adjacent areas in a continuous distribution to species that diverged several million years ago. At the finest scale, while some distance measures performed extremely well, statistics developed specifically to accommodate the mutational processes of microsatellites performed relatively poorly, presumably because of the relatively higher variance of these statistics. At the other extreme, no statistic was able to resolve the close sister relationship of polar bears and brown bears from more distantly related pairs of species. This failure is most likely due to constraints on allele distributions at microsatellite loci. At intermediate scales, both within continuous distributions and in comparisons to insular populations of late Pleistocene origin, it was not possible to define the point where linearity was lost for each of the statistics, except that it is clearly lost after relatively short periods of independent evolution. All of the statistics were affected by the amount of genetic diversity within the populations being compared, significantly complicating the interpretation of genetic distance data.
A CASE OF HIGH RATE OF SPONTANEOUS MUTATION AFFECTING VIABILITY IN DROSOPHILA MELANOGASTER
Authors: Kidwell Margaret Gale , Kidwell J F , Nei M
Published: January 2021

A spontaneous lethal mutation rate approximately twenty to thirty times greater than normal has been discovered in second and third chromosomes derived from an irradiated isogenic line and paired with marked inversion chromosomes. Mutations resulting in reductions of viability of varying magnitude short of complete lethality apparently also occur at a very high rate in the third but not in the second chromosome. The pattern of accumulation of lethal mutations over several generations and viability frequency distributions within generations have been studied in a number of independent experiments. High mutation rate occurs in heterozygous isogenic-derived second and third chromosomes, either together or apart, irrespective of the genetic constitution of nonhomologous chromosomes. High mutation rates were not observed using the same methods with chromosomes of an inbred line from a different source. The possible mechanisms responsible for these results are discussed.
INFLUENCE OF B LOCUS BLOOD GROUPS ON ADULT MORTALITY AND EGG PRODUCTION IN THE WHITE LEGHORN CHICKEN
Authors: Nordskog A W , Rishell W A , Briggs D M
Published: January 2021

The influence of the B locus blood group on adult viability and egg production was studied in two White Leghorn populations (S1 and S2) synthesized from inbred line crosses. Each line segregated for four B alleles. Four homozygotes and six heterozygotes were produced in each line over a five-year period, and for an additional three years tests on certain blood-group combinations were continued. A total of 4371 birds were included in the study. Greatest differences in blood groups were found in the S1 line, with the B2 and B21 alleles seemingly having favorable effects and with B1 having unfavorable effects. The B1 homozygote was consistently the lowest in egg production (53.2%) and highest adult mortality (40.4%). The relative spread in standard deviation units between the B1 and B2 homozygotes was more than three times greater in adult mortality than in egg production; B2 was incompletely dominant to B1. Within the S1 line, the superiority of the heterozygotes was mainly a consequence of the poor fitness of the B1 homozygote, suggesting that in a random-mated population B1 would be maintained only by mutation and not by a polymorphic mechanism.—Over the eight years of the experiment, adult viability of the B1 homozygote improved 4.4% per year (P<0.05). Assuming this regression results from natural selection, either of two hypotheses can account for the results: (1) The B locus is pleiotropic with natural selection for many B modifiers, and (2) the B locus is neutral but linked to a major fitness locus.
A QUANTITATIVE ANALYSIS OF THE GENETICS OF RESTING BLOOD LACTIC ACID LEVELS IN MICE
Authors: Hatchell Patricia L , MacInnes James W
Published: January 2021

Resting blood lactate levels were measured in inbred mouse strains, their F1, and several of their segregating generations to determine whether the level of lactic acid is influenced by genetic factors. The inbred strains in each of the two sets used differed significantly from one another for this character. Only one strain showed a significant sex difference. The data could not be fully analyzed because of the failure to fulfill Mather's first criterion for an adequate scale. Nonallelic interactions, in particular, additive x dominance and dominance x dominance, were found to influence the generation means. Genotype x environment interaction was detected and eliminated by log transformation. Negative heterosis was exhibited by all but one noninbred generation.—The data suggest that genes influencing the character are dispersed between the parental lines and that interactions are predominantly of the duplicate kind. A buffering system by which lactate levels are kept at a minimum is proposed.
GENETIC ANALYSES OF HEAT-SENSITVE PAWN MUTANTS OF PARAMECIUM AURELIA
Authors: Chang Sheng-Yung , Kung Ching
Published: January 2021

Heat-sensitive Pawn (ts Pawns) of Paramecium aurelia behaved normally when grown at 23° but failed to avoid strong stimuli at 35°. Four of the five ts Pawn lines tested were found to be allelic at a locus known also to carry temperature-independent Pawn mutations. The fifth ts Pawn line complemented all the conditional and unconditional Pawn mutants of the two known loci. This result, together with the patterns of F2 segregation from various crosses, suggested the existence of a third Pawn locus. An additive effect of the unlinked ts Pawn genes was observed. These findings and the significance of ts Pawns as experimental material in behavioral and physiological research are discussed.
HOMOEOSIS IN DROSOPHILA. I. COMPLEMENTATION STUDIES WITH REVERTANTS OF NASOBEMIA
Authors: Denell R E
Published: January 2021

A number of homoeotic mutants have been localized to the proximal right arm of chromosome 3 of Drosophila melanogaster. These include seven alleles of Antennapedia (Antp), which is associated with a transformation of antennae into legs; Nasobemia (Ns), which causes the same phenotype as Antp but was considered by Gehring (1966) not to be an allele; and three genes causing a transformation of second and third legs into first legs: Extra sex comb (Scx), Polycomb (Pc), and Multiple sex comb (Msc.). The alleles of Antp and Scx share a common recessive lethal effect, and Pc maps 0.2-0.3 units to the left of Scx.—In the present investigation, rearrangements associated with the reversion of Ns suggest that its cytological location is in or just distal to salivary chromosome doublet 84B1-2. Although Ns is viable when homozygous, four of its revertants share a common recessive lethal effect. These revertants fail to complement the recessive lethality of AntpB and Scx. Furthermore, they show a complex pattern of functional interaction with Pc and with Humeral (Hu), a dominant mutation associated with a rearrangement with one breakpoint just distal to 84B1-2. Finally, analysis of a revertant of Msc indicates that Msc is also located very close to 84B1-2. It is concluded that Ns and Scx are alleles of Antp. Pc shows many functional similarities to the Antp locus, but is probably not allelic. Evidence is presented that these dominant homoeotic genes are neomorphic in nature.
THE INTERACTION OF TWO COMPLEX LOCI, ZESTE AND BITHORAX IN DROSOPHILA MELANOGASTER
Authors: Kaufman T C , Tasaka S E , Suzuki D T
Published: January 2021

It has been found that certain alleles of the zeste locus (za 1-1.0) have no phenotype of their own, but interact with certain alleles at the bithorax locus (bx 3-58.8). This interaction takes the form of an enhancement of the homeotic bx phenotype to a more extreme form—i.e., the metathorax is transformed into mesothorax in varying degrees depending on the bx allele used. This enhancement is somewhat reminiscent of the transvection effect described by Lewis (1954). The characterization of the interaction thus far has shown that the enhancement only effects bx alleles which arise spontaneously, whereas the origin of the za allele is unimportant. The gene claret nondisjunctional was used for the production of gynandromorphs which showed that the enhancing ability of za, like the eye pigment change caused by z, is autonomous. The enhancement of one specific allele (bx34e), which is temperature-sensitive, has allowed a delineation of the temperature-sensitive period of the bithorax locus to a period extending from the middle of the second larval instar to the middle of the third larval instar. These results, as well as those of other enhancer and suppressor systems in Drosophila, have revealed the possibility of the involvement of heterocyclic compounds in the control of cell determination and fate in Drosophila melanogaster.
DEVELOPMENTAL AND GENETIC STUDIES ON KYNURENINE HYDROXYLASE FROM DROSOPHILA MELANOGASTER
Authors: Sullivan David T , Kitos Robert J , Sullivan Marie C
Published: January 2021

The level of kynurenine hydroxylase was measured throughout the development of wild type and the eye color mutants v, cn, st, ltd, cd, kar, w, ca, bri and pP of Drosophila melanogaster. In all cases except cn a bimodal distribution of enzyme activity during development was observed. Activity is initially detectable in second instar. A maximum is reached in early third instar. Activity declines prior to puparium formation. Shortly after pupation, activity rises dramatically to reach a maximum about five times the peak larval level. Maximum activity persists for a short time, and then falls sharply prior to emergence. No activity is detectable in cn, cn3, or cn35K. In pupae which have zero, one, two or three doses of the cn  + allele, activity is proportional to the number of the + alleles. This provides further evidence that the cn locus contains the structural gene for kynurenine hydroxylase. Kynurenine hydroxylase is a useful gene product for studying the events of imaginal disc differentiation.
UNSTABLE DIPLOIDS OF NEUROSPORA AND A MODEL FOR THEIR SOMATIC BEHAVIOR
Authors: Smith David A
Published: January 2021

When ascospores from crosses of certain strains were germinated under conditions selective for heterozygosity of complementing markers on one linkage group, a portion of the resulting colonies were also heterozygous for unselected markers on other chromosomes, implying multiple disomy. The frequency of disomy and the pattern of marker homozygosity are consistent with most or all multiple disomics having originated as complete diploids following nondisjunction at meiosis I. The production of diploid ascospores in these strains is apparently under polygenic control. The diploids are highly unstable and do not differ from n+1 disomics in rates and mechanisms of haploidization and mitotic crossing over.
TRANSLOCATIONS, THE PREDOMINANT CAUSE OF TOTAL STERILITY IN SONS OF MICE TREATED WITH MUTAGENS
Authors: Cacheiro Nestor L A , Russell Liane Brauch , Swartout Margaret S
Published: January 2021

Histological and cytological analyses of the testes were carried out in 42 sterile sons of males treated in the spermatozoal or spermatid stage with 250 mg/kg ethyl methanesulfonate (EMS) alone or after prefeeding with butylated hydroxytoluene (BHT); or treated with 200 R X-rays. Of the 42 sterile males, 17 had some mature spermatids, nine were blocked at diakinesis, 15 were blocked in pachytene, and one lacked spermatogenic cells altogether, having Sertoli cells only. Mitotic (spermatogonial) metaphases could therefore be analyzed in 41 of the males and meiotic configurations in 26.—(1) None of the males showed abnormalities in chromosome number, such as monosomy, trisomy, or mosaicism for either of these conditions. Certain classes of chromosome abnormalities that have been found associated with male sterility in other investigations, namely trisomies, XXY's, and X-autosome translocations, are not expected from treatment of 19A + Y cells when F1 males are studied. (2) A very high percentage of the sterile males carried translocations. Direct meiotic evidence for this was found in 22 of the animals. In addition, 11 of the 16 that were blocked (or virtually blocked) in pachytene, and thus could be analyzed in mitosis only, consistently showed one abnormally short chromosome (or, one short plus one long), which presumably had resulted from unequal exchange (or sizable deficiency). Of the meiotically detected translocation males, 1 carried a T(A;Y), 17 had single autosomal translocations, and 4 had multiple autosomal rearrangements involving three, four, four, and six breaks, respectively. In addition, three males showed failure of X-Y pairing. (3) Translocations that cause sterility, rather than partial sterility, in males appear to be those in which at least one of the breaks occurs close to one end of a chromosome. The mitotic and meiotic evidences for this were found to be correlated. (4) It is proposed that many cases of induced F1 male sterility may be the result of position effects produced when paracentromeric regions are translocated to euchromatic regions of certain other chromosomes. Since many translocations that produce partial sterility in the female cause complete sterility in the male, the male must be assumed to be more susceptible to disturbances of fertility by the postulated mechanism. (5) There is evidence that EMS, especially in the lower dose range, more often breaks chromosomes near one of their ends than does X-irradiation.
THE MECHANISM OF HETEROKARYOTIC GROWTH IN VERTICILLIUM DAHLIAE
Authors: Puhalla John E , Mayfield John E
Published: January 2021

Heterokaryons of Verticillium dahliae, forced between complementary auxotrophs, were stable at 21° and resembled the wild type morphologically. In such heterokaryons the hyphal cells were predominantly uninucleate, and no nuclear migration from cell to cell was observed. Heterokaryosis was apparently confined to binucleate, interhyphal, anastomosed cells that arose 1-2 mm behind the colony front. Such anastomosed cells thereby fed and maintained large homokaryotic areas including the colony edge. This stable mosaic colony is in sharp contrast to the heterokaryon of Neurospora.—Heterokaryons of V. dahliae cannot continue growth at 30° because the high temperature prevents hyphal anastomosis. Heterozygous diploids sector out from heterokaryons after 8-12 days at 30°. Interhyphal anastomosed cells are apparently the site of karyogamy.
Genomic regions associated with microdeletion/microduplication syndromes exhibit extreme diversity of structural variation
Authors: Mostovoy Yulia , Yilmaz Feyza , Chow Stephen K , Chu Catherine , Lin Chin , Geiger Elizabeth A , Meeks Naomi J L , Chatfield Kathryn C , Coughlin Curtis R , Surti Urvashi , Kwok Pui-Yan , Shaikh Tamim H
Published: January 2021

Segmental duplications (SDs) are a class of long, repetitive DNA elements whose paralogs share a high level of sequence similarity with each other. SDs mediate chromosomal rearrangements that lead to structural variation in the general population as well as genomic disorders associated with multiple congenital anomalies, including the 7q11.23 (Williams–Beuren Syndrome, WBS), 15q13.3, and 16p12.2 microdeletion syndromes. Population-level characterization of SDs has generally been lacking because most techniques used for analyzing these complex regions are both labor and cost intensive. In this study, we have used a high-throughput technique to genotype complex structural variation with a single molecule, long-range optical mapping approach. We characterized SDs and identified novel structural variants (SVs) at 7q11.23, 15q13.3, and 16p12.2 using optical mapping data from 154 phenotypically normal individuals from 26 populations comprising five super-populations. We detected several novel SVs for each locus, some of which had significantly different prevalence between populations. Additionally, we localized the microdeletion breakpoints to specific paralogous duplicons located within complex SDs in two patients with WBS, one patient with 15q13.3, and one patient with 16p12.2 microdeletion syndromes. The population-level data presented here highlights the extreme diversity of large and complex SVs within SD-containing regions. The approach we outline will greatly facilitate the investigation of the role of inter-SD structural variation as a driver of chromosomal rearrangements and genomic disorders.
Inference of population genetic parameters from an irregular time series of seasonal influenza virus sequences
Authors: Croze Myriam , Kim Yuseob
Published: January 2021

Basic summary statistics that quantify the population genetic structure of influenza virus are important for understanding and inferring the evolutionary and epidemiological processes. However, the sampling dates of global virus sequences in the last several decades are scattered nonuniformly throughout the calendar. Such temporal structure of samples and the small effective size of viral population hampers the use of conventional methods to calculate summary statistics. Here, we define statistics that overcome this problem by correcting for the sampling-time difference in quantifying a pairwise sequence difference. A simple linear regression method jointly estimates the mutation rate and the level of sequence polymorphism, thus providing an estimate of the effective population size. It also leads to the definition of Wright’s FST for arbitrary time-series data. Furthermore, as an alternative to Tajima’s D statistic or the site-frequency spectrum, a mismatch distribution corrected for sampling-time differences can be obtained and compared between actual and simulated data. Application of these methods to seasonal influenza A/H3N2 viruses sampled between 1980 and 2017 and sequences simulated under the model of recurrent positive selection with metapopulation dynamics allowed us to estimate the synonymous mutation rate and find parameter values for selection and demographic structure that fit the observation. We found that the mutation rates of HA and PB1 segments before 2007 were particularly high and that including recurrent positive selection in our model was essential for the genealogical structure of the HA segment. Methods developed here can be generally applied to population genetic inferences using serially sampled genetic data.
Polynomial Roth Theorems on Sets of Fractional Dimensions
Authors: Fraser Robert , Guo Shaoming , Pramanik Malabika
Published: January 2021

Let $E\subset{\mathbb{R}}$ be a closed set of Hausdorff dimension $\alpha \in (0, 1)$. Let $P: {\mathbb{R}}\to{\mathbb{R}}$ be a polynomial without a constant term whose degree is bigger than one. We prove that if $E$ supports a probability measure satisfying certain dimension condition and Fourier decay condition, then $E$ contains three points $x, x+t, x+P(t)$ for some $t>0$. Our result extends the one of Łaba and Pramanik [ 11] to the polynomial setting, under the same assumption. It also gives an affirmative answer to a question in Henriot et al. [ 7].
Weighted Spectral Cluster Bounds and a Sharp Multiplier Theorem for Ultraspherical Grushin Operators
Authors: Casarino Valentina , Ciatti Paolo , Martini Alessio
Published: January 2021

We study degenerate elliptic operators of Grushin type on the $d$-dimensional sphere, which are singular on a $k$-dimensional sphere for some $k < d$. For these operators we prove a spectral multiplier theorem of Mihlin–Hörmander type, which is optimal whenever $2k \leq d$, and a corresponding Bochner–Riesz summability result. The proof hinges on suitable weighted spectral cluster bounds, which in turn depend on precise estimates for ultraspherical polynomials.
The American College of Radiology/Society of Breast Imaging Updated Fellowship Training Curriculum for Breast Imaging
Authors: Katzen Janine T , Grimm Lars J , Brem Rachel F
Published: January 2021

Since the publication of the most recent breast imaging resident and fellowship curriculum in 2013, there have been widespread changes to the field of breast imaging. Screen-film mammography has been nearly completely replaced, and there has been widespread adoption of breast MRI and digital breast tomosynthesis. Fellowship training programs are increasingly one year in length, which accommodates the rapidly evolving subspecialized field of breast imaging. Recent surveys have identified deficits in nonclinical training related to patient communication and practice audits. This updated fellowship curriculum focuses on four discrete skill sets: clinical, noninterpretive, collaborative, and scholarly. Updates to the clinical curriculum include familiarity with new and emerging imaging technologies and biopsy techniques, as well as a more comprehensive understanding of breast pathology and appropriate follow-up and/or treatment recommendations. There is an increased focus on noninterpretive skills related to the practice audit and quality control. A formal communication curriculum tailored toward discussions with patients is highly recommended. The collaborative value of multidisciplinary care and the benefits of mentorship are emphasized. Finally, scholarly activities including both the opportunity for teaching and research, as well as dedicated lectures and journal clubs, will establish a platform for lifelong learning. This updated curriculum, which has been approved by the Executive Committee of the American College of Radiology and the Society of Breast Imaging Board of Directors, is designed to develop well-rounded fellowship graduates who are positioned to be breast imaging leaders within their future practices.
Spatiotemporal characteristics of the COVID-19 resurgence in the metropolitan wholesale market of Beijing, China
Authors: Wang Xin-Yu , Zhang Yu-Qi , Cai Li-Wen
Published: January 2021

Metropolitan wholesale markets are at high risk of coronavirus disease 2019 (COVID-19) spread as originally seen in Wuhan, China. We studied the metropolitan wholesale market-related resurgence of COVID-19 in Beijing, China, and highlight the importance of control strategies based on the temporospatial characteristics of wholesale markets.
Cultural Identity
Authors: Chen Yea-Wen , Mendy Marion G.
Published: January 2021

Cultural identity is a multidimensional concept that has fascinated scholars, researchers, and practitioners in (intercultural) communication and related disciplines over time. The year 2020 has witnessed renewed interests in and debates about a multiplicity of cultural identities, which demonstrate the concept’s relevance in everyday interactions across local and global contexts. For instance, both the rise of conservatism across the globe (including white nationalism in the United States during the Trump administration) and the push for greater equity and inclusion for all (e.g., Black Lives Matter movement, sexual misconduct policies, and gender-neutral bathrooms in public spaces) have garnered and regenerated needs to better understand cultural identity as a complex and contested communication construct. Analytically, cultural identity encompasses a wide range of socially constructed categories that influence how a person knows and experiences his/her/their social world (e.g., race, ethnicity, gender, nationality, socioeconomic status, ability, sexuality, religion, and more). As a social construct, cultural identity deals with important questions about conceptions, understandings, and lived experiences regarding the self in relation to others across time, space, and context. In particular, cultural identity—as opposed to identity—focuses on questions regarding membership in, acceptance into, (dis)identification with, and/or negotiation of (un)belongingness to various groups vis-à-vis communication. Questions about “difference” in a myriad of ways are at the heart of inquiries about cultural identity. That is, cultural identity is better understood as “cultural identities” as always already plural, intersecting, and evolving along various power lines that relate to histories, politics, and social forces. Communication scholars have studied the concept of cultural identity from different perspectives and approaches (e.g., functionalist, interpretive, and critical lenses). In this article, influential works are identified and reviewed in related fields such as psychology, sociology, and cultural studies that have shaped the study of cultural identity in (intercultural) communication in US academia. Then, core texts and articles in communication are considered that represent key issues, core debates, and central arguments about cultural identities, which are followed by textbooks and readers, a review of journals, and prominent theories of cultural identity by intercultural communication scholars in the United States. The article ends with major areas of study.
Hekla Revisited: Fractionation of a Magma Body at Historical Timescales
Authors: Geist Dennis , Harpp Karen , Oswald Peter , Wallace Paul , Bindeman Ilya , Christensen Branden
Published: January 2021

Hekla is an elongate volcano that lies at the intersection of the South Iceland Seismic Zone and the Eastern Volcanic Zone. We report major and trace element, oxygen isotopic, and H2O analyses on rocks, glass, melt inclusions, and minerals from almost all of the historical lavas and tephra deposits. This new dataset confirms the remarkable observation that not only are many eruptions compositionally zoned from felsic to mafic, but the extent of zoning relates directly to the length of repose since the previous eruption. Compositional data are consistent with the origin of the basaltic andesites and andesites by fractional crystallization, with no measurable crustal interaction once basaltic andesite has been produced. Although the 1104 CE Plinian rhyolite and 1158 CE dacite are also created by fractional crystallization, uranium–thorium isotopic disequilibria measured by others require that they evolved in a separate body, where magma is stored in a molten state for >104 years. Consistent trace element trends and ratios, as well as oxygenisotopic data, preclude significant crustal input into the evolving magma. The phenocryst assemblages are dominated by crystals that formed from their host melt; an exception is the 1158 CE dacite, which contains abundant crystals that formed from the 1104 CE rhyolite melt. A suite of thermobarometers indicates that most crystals formed in the lower crust at temperatures ranging from ∼1010 to 850 °C. Hekla’s unique and systematic petrological time series and geophysical activity are attributed to the unusual geometry of the magma body, which we propose to be a tabular, vertically elongate macrodike, extending from the lower to the upper crust. The vertical body is recharged with basaltic andesite magma at the end of each eruption, which then undergoes cooling and crystallization until the subsequent eruption. The entire system is supplied by a lower-crustal body of basaltic andesite, which is produced by fractional crystallization of basaltic magma in a reservoir that is thermochemically buffered to ∼1010 °C. Cooling and crystallization of recharged basaltic andesite magma in a background geothermal gradient from the lower to the shallow crust accounts for the systematic relationship between repose and composition.
The International Society for Behavioral Medicine (ISBM) and the Society of Behavioral Medicine (SBM) advocate for the inclusion of behavioral scientists in the implementation of the Global Action Plan for the prevention of non-communicable diseases (NCDs) in low- and middle-income countries
Authors: Odukoya Oluwakemi , Fox Rina S , Hayman Laura L , Penedo Frank J
Published: January 2021

Non-communicable diseases (NCDs) are the leading cause of death and disability in the world with the majority of deaths occurring in low- and middle-income countries (LMICs). The financial implications of disease and disability due to NCDs, combined with the costs of long-term management, are major causes of impoverishment and serve as barriers to socio-economic development. The transition from infectious diseases to NCDs as leading causes of mortality in LMICs is driven by several factors, primarily increasing globalization, urbanization, ageing of populations and economic development. Responding to these challenges will require local and comprehensive primary and secondary prevention efforts. The World Health Organization’s Global Action Plan provides a road map and an array of policy options to achieve nine voluntary global targets by 2025. The primary responsibility of governments in responding to the challenge of NCDs includes international scientific cooperation to support national and local efforts. The implementation of such efforts to prioritize the prevention of NCDs will create an environment in which the rising trend of the NCD burden could be potentially halted and reversed. When developing NCD policies, stakeholders should consider evidence-based strategies which can be implemented by multidisciplinary teams that are led or have the participation of behavioral medicine scientists. Behavioral medicine strategies should be incorporated into the policy and intervention framework developed to target NCDs in LMICs.
Identification and Characterization of Sphaerulina vaccinii sp. nov. as the Cause of Leaf Spot and Stem Canker in Lowbush Blueberry and Its Epidemiology
Authors: Ali Shawkat , Hildebrand Paul D. , Renderos Willy E. , Abbasi Pervaiz A.
Published: January 2021

Septoria leaf spot and stem canker is an important disease of lowbush blueberry, but the causal pathogen has not been accurately identified. Based on sequence analysis of the internal transcribed spacer, translation elongation factor 1 alpha, RNA polymerase II second largest subunit, 28S nuclear ribosomal DNA gene, and β-tubulin genes, the pathogen aligns closely with the genus Sphaerulina. The phylogenetic analyses based on these loci demonstrate that while the pathogen is closely related to the species Sphaerulina amelanchier, it is sufficiently distinct to warrant a new species designation. No ascomata of the teleomorph were found; however, ascospores recovered from leaves fit, morphologically, with the genus Mycosphaerella. The morphological data also support a new species designation. Based on the host that this pathogen infects, we propose the name as Sphaerulina vaccinii and the disease as Sphaerulina leaf spot and stem canker. Under field conditions, it appears that initial inoculum originates from pycnidia on overwintered leaves and stem lesions (cankers) on fruiting stems. More than 90% of the initial inoculum was released during the flowering period from late May through June. Leaf spots began to appear in early June and disease severity increased in a linear manner over time. Secondary inoculum production from diseased foliage was minimal and not considered important epidemiologically. Defoliation resulting from disease began in early July and increased in a nonlinear manner thereafter. Manual defoliation of blueberry stems at various times prior to harvest showed the substantial extent to which premature defoliation by this disease can affect yield. Stem lesions were also shown to have an impact on yield, even though stems were not killed.
COVID-19, Personal Protective Equipment, and Human Performance
Authors: Ruskin Keith J. , Ruskin Anna Clebone , Musselman Brian T. , Harvey Jaime Rivas , Nesthus Thomas E. , O’Connor Michael
Published: January 2021

Clinicians who care for patients infected with coronavirus disease 2019 (COVID-19) must wear a full suite of personal protective equipment, including an N95 mask or powered air purifying respirator, eye protection, a fluid-impermeable gown, and gloves. This combination of personal protective equipment may cause increased work of breathing, reduced field of vision, muffled speech, difficulty hearing, and heat stress. These effects are not caused by individual weakness; they are normal and expected reactions that any person will have when exposed to an unusual environment. The physiologic and psychologic challenges imposed by personal protective equipment may have multiple causes, but immediate countermeasures and long-term mitigation strategies can help to improve a clinician’s ability to provide care. Ultimately, a systematic approach to the design and integration of personal protective equipment is needed to improve the safety of patients and clinicians.
Congenital Ewing Sarcoma Presenting as a Rapidly Growing Neck Mass in a Newborn
Authors: De Sa Hong , Pearl John , Hibbs Anna Maria , Pereda Maria , Suzuki Izumi , Curtis Sean , Stearns Duncan
Published: January 2021

Background:

Ewing sarcoma (EWS) is an aggressive soft-tissue and bone malignancy. Congenital EWS is extremely rare, and its presenting features can be unique from that of EWS occurring in older children.

Clinical Findings:

A full-term female infant with a neck mass present at birth was admitted to a level I nursery with an otherwise well appearance and normal vital signs. After consultation with a neonatologist, she was transferred to a neonatal intensive care unit where she developed sudden respiratory collapse from rapid growth of the mass causing airway obstruction, leading to emergent intubation. Ultrasound and MRI scans of the neck mass demonstrated cystic and vascular components, and a timely biopsy revealed small round blue cells with diffuse CD99 expression and chromosomal translocation 11;22.

Primary Diagnosis:

Ewing sarcoma.

Interventions:

An accelerated workup for EWS was done due to the patient's critical status. On day of life (DOL) 8, she was started on treatment of EWS as per the current standard-of-care AEWS0031. On DOL 24, she underwent tracheostomy placement.

Outcomes:

The patient completed 14 total cycles of chemotherapy and is more than 12 months old. Her tracheostomy was decannulated at 6 months of age.

Practice Recommendations:

The rarity of EWS in neonates and its presentation as a neck mass make this disease difficult to recognize unless clinicians have a high index of suspicion. The aims of this case report are to increase awareness of malignancy as a potential cause of neck masses in neonates and to prompt nurses and physicians to prepare for airway stabilization at appropriate levels of care if a neck mass is present at birth.