bluuebunny/crossref_metadata_2025_split huggingface dataset:
USE OF GENETIC EFFECTS AND GENOTYPE BY ENVIRONMENTAL INTERACTIONS FOR THE CLASSIFICATION OF MEXICAN RACES OF MAIZE
Authors: Cervantes Tarcicio S , Goodman Major M , Casas Eduardo D , Rawlings John O 
Published: April 2021

ABSTRACT
To examine the questions of whether the additive and dominance effects present for morphological characters in racial crosses are of sufficient consistency and magnitude to allow such genetic effects to be used for racial classification, we used a diallel experiment among the 25 well-defined Mexican races of maize, which include the ancestral stocks of most commercial and genetic maize types. With such an experiment, genetic effects and genotype by environmental interactions for one or more characters can be used to measure genetic and adaptational or environmental similarity. We used average parental effects (general combining abilities), specific effects, and genotype by environmental effects of 21 characters from the diallel (grown at three locations) to group the Mexican races of maize. The groupings based upon average genetic effects and upon genotype by environmental interactions are more satisfactory than groupings based upon specific effects. The standard errors for genetic distances based upon specific (largely dominance) effects seem to be too high for practical use. Principal components analyses of the same data suggest a similar conclusion.—The groupings based upon average genetic effects are in general agreement with previous studies, with the exception of Maíz Dulce, which is grouped with the Cónicos, rather than being isolated from the other Mexican races of maize.
SITE SPECIFICITY AND VARIABILITY IN THE MUTATOR AND ANTIMUTATOR EFFECTS OF PHAGE T4 GENE 43 MUTANTS
Authors: Ronen Amiram , Halevy Calomira , Kass Nava 
Published: April 2021

ABSTRACT
Spontaneous, 2-aminopurine- and 5-bromouracil-induced mutations at six rII nonsense codons were studied in phage T4 strains possessing wild-type and mutant gene 43 alleles. The mutation pathways studied included interconversions and reversions of nonsense codons. The tsCB87 allele, which specifies an antimutator DNA polymerase, reduced base-analogue-induced mutation frequencies along all pathways. However, GC base pairs were less affected than AT base pairs. The frequency of spontaneous UAA→UAG conversions was also reduced by tsCB87, but that of spontaneous UAA→UGA conversions was often increased. Mutation in the presence of the mutator allele tsL56 was increased along all pathways, with no preference for either AT or GC base pairs. Mutation frequencies in the presence of the two mutant DNA polymerases were highly variable. A strong correlation was found between 2-aminopurine-induced mutation frequencies in ts + and tsCB87 phage along the reversion and UAA→UAG (but not UAA→UGA) pathways.
NONDISJUNCTION MUTANTS OF THE NEMATODE CAENORHABDITIS ELEGANS
Authors: Hodgkin Jonathan , Horvitz H Robert , Brenner Sydney 
Published: April 2021

ABSTRACT
The frequency of males (5AA; XO) among the self progeny of wild-type Caenorhabditis elegans hermaphrodites (5AA; XX) is about one in 500. Fifteen him (for "high incidence of males") mutations have been identified that increase this frequency by a factor of ten to 150, as a result of increased X-chromosome nondisjunction. The mutations define ten complementation groups, which have been mapped: nine are autosomal, and one sex linked. Most of the mutants are superficially wild type in anatomy and behavior; however, him-4 mutants display gonadal abnormalities, and unc-86 mutants, which have a Him phenotype, exhibit a variety of anatomical and behavioral abnormalities. All the mutants segregate fertile 3X hermaphrodite progeny as well as XO male progeny, Some produce large numbers of inviable zygotes. Mutants in all ten genes produce diplo-X and nullo-X exceptional ova, and in the four strains tested, diplo-X and nullo-X exceptional sperm are produced by 2X "transformed" males. It appears likely that most of the mutants have defects in both gamete lines of the hermaphrodite. XO males of him strains other than him-4 and unc-86 are similar to wild-type males in anatomy and behavior, and all produce equal or almost equal numbers of haplo-X and nullo-X sperm, and no diplo-X sperm. Male fertility is reduced to varying extents in all him mutants. In four of the strains, nondisjunction during oogenesis has been shown to occur at a reductional division, and in three of these strains, abnormalities in recombination have been demonstrated. One mutant also exhibits autosomal nondisjunction, but many of the others probably do not. Therefore, the X chromosome of C. elegans may differ from the autosomes in the mechanisms controlling its meiotic behavior.——3x hermaphrodites are shorter and less fertile than 2X hermaphrodites, and they produce many inviable zygotes among their self progeny: these are probably 4X zygotes. Haplo-X and diplo-X ova are produced in 2:l ratio by 3X hermaphrodites. him mutations are expressed in these animals, increasing the frequency of self-progeny males and 2X hermaphrodites.
GENETIC ANALYSIS OF THE ACHAETE-SCUTE SYSTEM OF DROSOPHILA MELANOGASTER
Authors: García-Bellido A 
Published: April 2021

ABSTRACT
Several mutations in the achaete-scute region of Drosophila have been analyzed phenotypically and cytologically. One group of them corresponds to point mutations, another t o rearrangements with one breakpoint in this region. Trans heterozygotes of the different point mutations or of the different rearrangements show poor complementation or fail to complement; therefore, they could be interpreted as mutations affecting the same gene product. However, left-right inversion recombinants and duplication-deficiency combinations between rearrangements with different cytological breakpoints uncover a complex organization of the achaete-scute region. This region seems to contain several independent achaete and scute functions, as well as a lethal function, arranged as a tandem reverse repeat at both sides of a lethal locus. Since all of the mutants show the same phenotype qualitatively, though different quantitatively, we suggest that these functions are of a reiterative nature. The achaete-scute wild-type condition may well be dependent on a multimeric gene product made of several evolutionary related monomers.
POPULATION DYNAMICS OF SEX-DETERMINING ALLELES IN HONEY BEES AND SELF-INCOMPATIBILITY ALLELES IN PLANTS
Authors: Yokoyama Shozo , Nei Masatoshi 
Published: April 2021

ABSTRACT
Mathematical theories of the population dynamics of sex-determining alleles in honey bees are developed. It is shown that in an infinitely large population the equilibrium frequency of a sex allele is l/n, where n is the number of alleles in the population, and the asymptotic rate of approach to this equilibrium is 2/(3n) per generation. Formulae for the distribution of allele frequencies and the effective and actual numbers of alleles that can be maintained in a finite population are derived by taking into account the population size and mutation rate. It is shown that the allele frequencies in a finite population may deviate considerably from l/n. Using these results, available data on the number of sex alleles in honey bee populations are discussed. It is also shown that the number of self-incompatibility alleles in plants can be studied in a much simpler way by the method used in this paper. A brief discussion about general overdominant selection is presented.
MAXIMUM LIKELIHOOD ESTIMATION OF LINKAGE AND INTERFERENCE FROM TETRAD DATA
Authors: Snow Richard 
Published: April 2021

ABSTRACT
Maximum likelihood equations have been derived for estimation of map distance and interference from two-point and ranked tetrad data. The estimators have been applied to data from Saccharomyces cerevisiae and Schizosac-charomyces pombe. S. cerevisiae consistently shows quite strong interference over the mapped genome. In striking contrast, S. pombe consistently shows much weaker interference and many crosses exhibit negative interference. In neither species was there a conspicuous tendency for intervals spanning a centromere to show less interference than those that did not. Since the amount of recombination per microgram of DNA in the two species is similar, the difference in interference characteristics seems to be a reflection of some fundamental difference in the recombination process of the two species.
REALIGNMENT OF THE GENETIC MAP OF THE TERMINUS OF THE rIIB CISTRON OF BACTERIOPHAGE T4
Authors: Parma David H , Dill Marsha , Slocum Mary K 
Published: April 2021

ABSTRACT
Duplication end-point mapping in the rIIB cistron indicates that the order of the B8-Bl0b segments is the inverse of that presented in BENZER'S (1961) genetic maps. This finding is supported by two- and three-factor crosses and the phenotypes of rII deletions extending into the D region.
ESCHERICHIA COLI K-12 AUXOTROPHS INDUCED BY INSERTION OF THE TRANSPOSABLE ELEMENT Tn5
Authors: Shaw Karen J , Berg Claire M 
Published: April 2021

ABSTRACT
The siies of insertion of the transposable kanamycin-neomycin resistance determining element, Tn5, in the E. coli K-12 chromosome were assessed in a collection of over 300 auxotrophs. Although mutations in at least 45 different cistrons were obtained, the distribution of insertion sites was not completely random: proA or proB; cysG; and cysH, cysD or cysC mutants were found in excess.
THE GENETICS OF HEXOKINASE IN A MOSQUITO, CULEX PIPIENS
Authors: Cheng Min-Lee , Hacker Carl S 
Published: April 2021

ABSTRACT
The genetics of hexokinase (HK) variants in a mosquito, Culex pipiens L., was studied using starch gel electrophoresis. Three isozymic forms of HK, all migrating anodally, were present in all three body regions, but in differing pmportions. No obvious difference in specificity for three hexose sugars was detected among the three isozymic bands. However, qualitative differences in staining intensity indicate the following order of substrate affinity: glucose &gt; fructose &gt; mannose. The inheritance of the HK variants is controlled by a pair of co-dominant alleles at a single genetic locus.
SUPPRESSION OF THE FORMATION OF POLYGENOTYPIC RECOMBINANT COLONIES BY A maf MUTATION IN MATING WITH HfrH
Authors: Ou Jonathan T , Kuo Li-Mei 
Published: April 2021

ABSTRACT
W3011, a Cavalli-type Hfr (HfrC), was mated with F-KY9474, maf-1, which cannot maintain F or F-like plasmids, and with F-OU9474, Maf+, a spontaneous revertant of KY9474. The recombinant colonies obtained were 100% monogenotypic from KY9474 and 90% monogenotypic from OU9474. On the other hand, in matings with OU11, a Hayes-type Hfr (HfrH), and these two F-strains, recombinant colonies derived from KY9474 showed only 22% polygenotypic recombinant colonies; whereas, those derived from OU9474 showed a high production rate (57%) of polygenotypic recombinant colonies. Among the polygenotypic recombinant colonies derived from KY9474 maf-1, 50% contained three or more recombinant types. These were probably derived from a small fraction of Maf+ revertants in the KY9474 population, as suggested by the results of mating this strain with M80, an F′ strain that contains an amber mutation in traH. These results support the hypothesis that the donor DNA fragments derived from an HfrH can undergo a limited replication in the recipient to produce polygenotypic recombinant colonies, whereas those derived from HfrC cannot.
POLYPLOIDS AND SEX DETERMINATION IN CAENORHABDITIS ELEGANS
Authors: Madl James E , Herman Robert K 
Published: April 2021

ABSTRACT
Tetraploid stocks of Caenorhabditis elegans var. Bristol carrying autosomal and X-linked markers have been produced. Tetraploid hermaphrodites fall into two categories: those that give about 1% male self-progeny and those that give 25 to 40% male self-progeny, The former are basically 4A;4X—four sets of autosomes and four sex chromosomes—and the latter are 4A;3X. Males are 4A;2X. (Diploid hermaphrodites are 2A;2X; males are 2A;IX.) Triploids wsre produced by crossing tetraploid hermaphrodites and diploid males. Triploids of composition 3A;3X are hermaphrodites; 3A;2X animals are fertile males. Different X-chromosome duplications were added to a 3A;2X chromosome constitution to increase the X-to-autosome ratio. Based on the resulting sexual phenotypes, we conclude that there exists on the C. elegans X chromosome at least three (and perhaps many mare) dose-sensitive sites that act cumulatively in determining sex.
FREQUENCY- AND DENSITY-DEPENDENT SELECTION ON A QUANTITATIVE CHARACTER
Authors: Slatkin Montgomery 
Published: April 2021

ABSTRACT
The equilibrium distribution of a quantitative character subject to frequency- and density-dependent selection is found under different assumptions about the genetical basis of the character that lead to a normal distribution in a population. Three types of models are considered: (1) one-locus models, in which a single locus has an additive effect on the character, (2) continuous genotype models, in which one locus o r several loci contribute additively to a character, and there is an effectively infinite range of values of the genotypic contributions from each locus, and (3) correlation models, in which the mean and variance of the character can change only through selection at modifier loci. I t is shown that the second and third models lead to the same equilibrium values of the total population size and the mean and variance of the character. One-locus models lead to different equilibrium values because of constraints on the relationship between the mean and variance imposed by the assumptions of those models.—The main conclusion is that, at the equilibrium reached under frequency- and density-dependent selection, the distribution of a normally distributed quantitative character does not depend on the underlying genetic model as long as the model imposes no constraints on the mean and variance.
GENETIC CONTROL OF MALATE DEHYDROGENASE ISOZYMES IN MAIZE
Authors: Goodman M M , Stuber C W , Lee C N , Johnson F M 
Published: April 2021

ABSTRACT
At least six nuclear loci are responsible for the genetic control of malate dehydrogznase (L-malate: NAD oxidoreductase; EC 1.1 .I .37; MDH) in coleoptiles of maize. Three independently segregating loci (Mdh1, Mdh2, Mdh3) govern the production of MDH isozymes resistant to inactivation by ascorbic acid and found largely or solely in the mitochondria. A rare recessive allele found at a fourth nuclear locus (mmm) causes increased electrophoretic mobility of the MDH isozymes governed by the Mdh1, Mdh2 and Mdh3 loci. -Two loci (Mdh4, Mdh5) govern MDH isozymes that are selectively in- activated by homogenization in an ascorbic acid solution and that appear to be nonmitochondrial (soluble). Mdh4 and Mdh5 segregate independently of each other and independently of Mdhl, Mdh2 and Mdh3. However, there is close linkage between the migration modifier and Mdh4.—Multiple alleles have been found for all of the Mdh loci except the migration modifier, and electrophoretically "null" or near "null" alleles (as expressed in standardized sections of maize coleoptile) have been found for all loci except Mdh4. Duplicate inheritance commonly occurs for Mdhl and Mdh2 and also for Mdh4 and Mdh5.—Inter- and intragenic heterodimers are formed between sub-units specified by the three loci governing the mitochondrial MDH isozymes. The same is true of the alleles and nonalleles at the two loci governing the soluble variants. No such heterodimers are formed by interactions between mitochondrial and soluble MDH isozymes.
CYTOKININ AUTONOMY IN TISSUE CULTURES OF PHASEOLUS: A GENOTYPE-SPECIFIC AND HERITABLE TRAIT
Authors: Mok Machteld C , Mok David W S , Armstrong Donald J , Rabakoarihanta Aimée , Kim Sang-Gu 
Published: April 2021

ABSTRACT
Intra- and interspecific differences in cytokinin requirement were detected in callus cultures of Phaseolus vulgaris L. and P. lunatus L. Of the ten geno-types of P. uulgaris tested in the present study, one required cytokinin for callus growth, six exhibited some to moderate growth on cytokinin-free medium, and the remaining three grew uniformly in the absence of cytokinin. In contrast, six of the P. lunatus genotypes were strictly cytokinin-dependent, while four genotypes displayed irregular amount of callus growth on cytokinin-free medium. The genotype-specific behavior of Phaseolus callus tissues was independent of the tissue of origin and the time in culture. The inheritance of the cytokinin requirement of Phareolus tissue cultures was studied in hybrid tissues resulting from crosses between a strictly cytokinin-dependent genotype (P.I. 2aO960) and two independent genotypes (cv. G 50 and P.I. 286303) of P . vulgaris. Fresh weights of hybrid tissues on cytokinin-free medium were intermediate between and significantly different from the parental tissues. No differences were found between reciprocal hybrids. These results suggest that cytokinin autonomy in tissue cultures of P. uulgaris is a genetic trait under nuclear control. Both parental and intermediate phenotypes were recovered in the F, progeny. The frequency distribution of cytokinin-dependent progeny in F, and backcross populations indicates that the cytokinin requirement of P. vulgaris callus tissue may be regulated by one set of alleles.
GENETIC VARIANCE AND CORRELATION AFTER SELECTION FOR TWO TRAITS BY INDEX, INDEPENDENT CULLING LEVELS AND EXTREME SELECTION
Authors: Bennett G L , Swiger L A 
Published: April 2021

ABSTRACT
Three two-trait selection methods were analyzed for their effects on genetic variance and correlation by multivariate methods, two-locus methods and computer simulation. The two-trait selection methods studied were independent culling levels (ICL), index (IND) and extreme (EXT) selection. The effects of the selection methods on genetic variance and correlation were partitioned into permanent effects due to changes in gene frequencies and temporary effects due to nonrandom association of alleles at different loci. Multivariate methods were used to predict temporary effects from a single generation of selection by each method and from several generations of index selection. Two-locus theory was used to determine the stability and rank of temporary effects on genetic correlation for all three methods. Predictions were compared to computer simulation results. When selection increased the means of both traits, EXT had the lowest (closest to,—l.O) genetic correlation and highest variances, while ICL tended to have the highest (closest to 1.0) genetic correlation. When selection increased the mean of one trait and decreased the mean cjf the other, EXT had the highest genetic variances and correlation, while ICL had the lowest genetic variances and correlation.
LINKAGE DISEQUILIBRIUM IN A FINITE POPULATION THAT IS PARTIALLY SELFING
Authors: Golding G B , Strobeck C 
Published: April 2021

ABSTRACT
The linkage disequilibrium expected in a finite, partially selfing population is analyzed, assuming the infinite allele model. Formulas for the expected sum of squares of the linkage disequilibria and the squared standard linkage disequilibrium are derived from the equilibrium values of sixteen inbreeding coefficients required to describe the behavior of the system. These formulas are identical to those obtained with random mating if the effective population size Ne = (l—½S)N and the effective recombination value re = (l-S)r/(l-½S), where S is the proportion of selfing, are substituted for the population size and the recombination value, Therefore, the effect of partial selfing at equilibrium is to reduce the population size by a factor 1 — ½S and the recombination value by a factor (l-S)/(l—½S).
THE TIMING OF Mu ACTIVITY IN MAIZE
Authors: Robertson Donald S 
Published: April 2021

ABSTRACT
The timing of mutator activity of Mu in maize was tested in three ways: (1) by allelism tests of phenotypically similar male-transmitted mutants, (2) by studying the clustering of phenotypically similar mutants as demonstrated by ear maps and the subsequent allelism tests of these mutants, and (3) by the induction of somatic sectors in Mu plants heterozygous for plant and endosperm marker genes. Allelism tests of phenotypically similar mutants in out-crosses of Mu plants as males established that 18.8% were allelic and that premeiotic mutants are induced. This conclusion was supported by ear maps of Mu-bearing plants, which revealed sectors of seeds that produced plants bearing phenotypically similar allelic mutants. The smallness of these sectors indicated that the premeiotic activity of Mu that gave rise to them occurred very late. The lack of visible sectors in mature sporophytic, endosperm and aleurone tissue in plants carrying Mu supports the conclusion that the mutator activity of Mu does not occur throughout the ontogeny of the plant and seems to be restricted to a time shortly before and/or during meiosis.
CONDITIONALLY EXPRESSED MISSENSE MUTATIONS: THE BASIS FOR THE UNUSUAL PHENOTYPE OF AN APPARENT trpD NONSENSE MUTANT OF SALMONELLA TYPHIMURIUM
Authors: Tanemura Shigeji , Bauerle Ronald 
Published: April 2021

ABSTRACT
Tryptophan auxotroph trp-28 is anomalous since preliminary mapping and suppression studies indicate the presence of a single amber nonsense mutation either late in trpE or early in trpD, but enzymological tests indicate the complete inactivation of both genes in this strain. Since the trpE and trpD genes are contiguous and encode the two subunits of a multifunctional enzyme complex, it was of interest to learn the mechanism of action of this apparent pleiotropic nonsense mutation. Our study has revealed that the phenotype of this strain derives not from a single mutation, but from the presence and interaction of multiple mutations. Besides the recognized amber mutation (designated trpD28), this strain carries two additional, conditionally expressed missense mutations (designated trpEl651 and trpD1652). The trpD28 amber codon maps in the promoter-proximal region 1 of trpD and eliminates the glutamine amidotransferase activity of the bifunctional trpD polypeptide. The trpD1652 mutation maps in the promoter-distal region 2 of trpD and severely reduces (but does not eliminate) the phosphoribosyl transferase activity of the trpD polypeptide. The trpE1651 mutation maps in the anterior part of trpE and causes a rapid loss of activity of the trpE polypeptide, but only when it exists as an uncomplexed subunit. The existence of the two missense mutations escaped prior notice in standard recombinational tests since the nature of each mutation is such that neither is detectable by the nutritional screens normally used in such tests unless an unsuppressed chainterminating mutation, such as trpD28, is also present.
GENETIC CHANGES WITH GENERATIONS OF ARTIFICIAL SELECTION
Authors: Silvela Luis 
Published: April 2021

ABSTRACT
Using conditional probabilities and moment-generating matrices, I derived approximate algebraic equations that give expectations of gene frequency, population mean, gene frequency variance within lines, or heterozygosity, and gene frequency variance between lines, or drift, for repeated cycles of recurrent selection in populations of finite size. For genes of large effect, the responses to selection differ substantially from the classical expectations, and equations are derived that give quantitative estimates of asymmetry of response when selection is done in opposite directions. Particular cases of the derived formulae yield equations given by other authors. The error involved in the approximations is discussed in the APPENDIX.
BIOCHEMICAL DIFFERENCES BETWEEN PRODUCTS OF THE Adh LOCUS IN DROSOPHILA
Authors: McDonald John F , Anderson Steven M , Santos Mauro 
Published: April 2021

ABSTRACT
An analysis of the molecular properties of the major alcohol dehydrogenase (E.C.1.1.1.1) allozyme variants found segregating in natural populations of D. melanogaster is presented. Our results indicate: (1) ADH-S enzyme has generally lower Michaelis-Menten constants than those of ADH-F; (2) ADH-S and ADH-F enzymes display opposite interactions for both co-factor and substrate; and (3) higher levels of ADH are associated with the Adh-fast genotype. The possible adaptive significance of these findings is discussed.