bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short‐term rates of parasite evolution predict the evolution of host diversity
Authors: BUCKLING A. , HODGSON D. J. 
Published: July 2007

AbstractCoevolution with parasites has been implicated as an important factor driving the evolution of host diversity. Studies to date have focussed on gross effects of parasites: how host diversity differs in the presence vs. absence of parasites. But parasite‐imposed selection is likely to show rapid variation through time. It is unclear whether short‐term fluctuations in the strength of parasite‐imposed selection tend to affect host diversity, because increases in host diversity are likely to be constrained by both the supply of genetic variation and ecological processes. We followed replicate populations of coevolving, initially isogenic, bacteria and phages through time, measuring host diversity (with respect to bacterial colony morphologies), host density and rates of parasite evolution. Both host density and time‐lagged rates of parasite evolution were good independent predictors of the magnitude of bacterial within‐ and between‐population diversities. Rapid parasite evolution and low host density decreased host within‐population diversity, but increased between‐population diversity. This study demonstrates that short‐term changes in the rate of parasite evolution can predictably drive patterns of host diversity.
Evolutionary biology of starvation resistance: what we have learned from Drosophila
Authors: RION S. , KAWECKI T. J. 
Published: July 2007

AbstractMost animals face periods of food shortage and are thus expected to evolve adaptations enhancing starvation resistance (SR). Most of our knowledge of the genetic and physiological bases of those adaptations, their evolutionary correlates and trade‐offs, and patterns of within‐ and among‐population variation, comes from studies on Drosophila. In this review, we attempt to synthesize the various facets of evolutionary biology of SR emerging from those studies. Heritable variation for SR is ubiquitous in Drosophila populations, allowing for large responses to experimental selection. Individual flies can also inducibly increase their SR in response to mild nutritional stress (dietary restriction). Both the evolutionary change and the physiological plasticity involve increased accumulation of lipids, changes in carbohydrate and lipid metabolism and reduction in reproduction. They are also typically associated with greater resistance to desiccation and oxidative stress, and with prolonged development and lifespan. These responses are increasingly seen as facets of a shift of the physiology towards a ‘survival mode’, which helps the animal to survive hard times. The last decade has seen a great progress in revealing the molecular bases of induced responses to starvation, and the first genes contributing to genetic variation in SR have been identified. In contrast, little progress has been made in understanding the ecological significance of SR in Drosophila; in particular it remains unclear to what extent geographical variation in SR reflect differences in natural selection acting on this trait rather than correlated responses to selection on other traits. Drosophila offers a unique opportunity for an integrated study of the manifold aspects of adaptation to nutritional stress. Given that at least some major molecular mechanisms of response to nutritional stress seem common to animals, the insights from Drosophila are likely to apply more generally than just to dipterans or insects.
Linking Morphological and Behavioural Defences: Prey Fish Detect the Morphology of Conspecifics in the Odour Signature of their Predators
Authors: Chivers Douglas P. , Zhao Xiaoxia , Ferrari Maud C. O. 
Published: July 2007

AbstractPredation is a strong selective force acting on both morphology and behaviour of prey animals. While morphological defences (e.g. crypsis, presence of armours or spines or specific body morphologies) and antipredator behaviours (e.g. change in foraging or reproductive effort, or hiding and fleeing behaviours) have been widely studied separately, few studies have considered the interplay between the two. The question raised in our study is whether antipredator behaviours of a prey fish to predator odours could be influenced by the morphology of prey conspecifics in the diet of the predator. We used goldfish (Carassius auratus) as our test species; goldfish exposed to predation risk significantly increase their body depth to length ratio, which gives them a survival advantage against gape‐limited predators. We exposed shallow‐bodied and deep‐bodied goldfish to the odour of pike (Esox lucius) fed either form of goldfish. Deep‐bodied goldfish displayed lower intensity antipredator responses than shallow‐bodied ones, consistent with the hypothesis that individuals with morphological defences should exhibit less behavioural modification than those lacking such defences. Moreover, both shallow‐ and deep‐bodied goldfish displayed their strongest antipredator responses when exposed to the odour of pike fed conspecifics of their own morphology, indicating that goldfish are able to differentiate the morphology of conspecifics through predator diet cues. For a given individual, predator threat increases as the prey become more like the individual eaten, revealing a surprising level of sophistication of chemosensory assessment by prey fish.
Ecological Risk Aversion and Foraging Behaviors of Juvenile Squirrel Monkeys (Saimiri sciureus)
Authors: Stone Anita I. 
Published: July 2007

AbstractThe ‘ecological risk aversion hypothesis’ [C.H. Janson and C.P. van Schaik, Juvenile Primates, Oxford Univ. Press, New York (1993), pp. 57–74] proposes that the pattern of slow growth characteristic of juvenile primates is a response to ecological risks (predation and starvation) experienced by juveniles. Juveniles are thought to avoid predation risk by positioning themselves near conspecifics, therefore experiencing high levels of feeding competition with older individuals, reduced access to resources and, consequently, high starvation risks during periods of food scarcity. The present study compared the foraging behaviors of juvenile and adult squirrel monkeys, a small neotropical primate characterized by a long juvenile period, to determine how predation and starvation risks affected juvenile behaviors. The study was conducted in Eastern Amazonia, in a seasonal environment. Due to their slow development, small body size and large group sizes, it was expected that juveniles in this species would behave in a manner consistent with the risk aversion hypothesis. However, age differences in foraging efficiency and foraging success were smaller than predicted. There was also no evidence that juveniles sacrificed access to food for predator protection. Adults did not have preferential access to fruit patches and direct competition was rare. Feeding competition for prey, the most common resource in the troop's diet, was negligible. Therefore, the slow growth and long juvenile period of squirrel monkeys do not correspond with evidence of predation or starvation risk, as predicted by the risk aversion hypothesis.
Monogynous Mating Behaviour and its Ecological Basis in the Golden Orb Spider Nephila fenestrata
Authors: Fromhage Lutz , Jacobs Kerstin , Schneider Jutta M. 
Published: July 2007

AbstractMales, especially in species where they provide little or no parental investment, usually have high potential reproductive rates and are expected to maximize their fitness by mating with several females. This view is challenged, however, by species in which males provide no parental investment, but nevertheless mate with one female only. Male monogamy (monogyny), associated with an extreme investment in paternity protection, appears to be comparatively common in web‐building spiders, and has recently been subject to experimental and theoretical studies. To date, however, studies approaching this issue from an ecological perspective are rare. Theory predicts that the evolution of a monogynous mating strategy is favoured by a male‐biased sex ratio, but not necessarily by a high mortality risk for mate‐searching males. To test these predictions, we conducted a field study on the golden orb spider Nephila fenestrata, which has a mating system with potentially cannibalistic, polyandrous females, and males that are often functionally sterile after mating with one female only. Based on daily observations of marked individuals, we confirm that, consistent with laboratory findings, monogyny is common in N. fenestrata. Nevertheless, observations of male movements between females raise the possibility that a proportion of males may mate with two females. We show that the sex ratio in our study population is male‐biased, and that males incur only a relatively moderate mortality risk during mate‐search. These findings provide insights into the ecological basis for the evolutionary maintenance of monogyny.
Within and Between Species Variation in Male Mating Behaviors in the Mexican Sailfin Mollies Poecilia velifera and P. petenensis
Authors: Hankison Shala J. , Ptacek Margaret B. 
Published: July 2007

AbstractPolymorphism in male morphology is often correlated with the expression of alternate behavioral tactics. This relationship between behavioral and morphological polymorphisms, however, is less well understood. We characterized male mating behaviors and morphological variation within and between Poecilia velifera and P. petenensis to understand mating signal evolution in the sailfin molly lineage. In addition, we examined whether differences between these species in the size range of mature males and the strength of allometry between dorsal fin size and body length could explain the variation observed in their expression of different mating behaviors. We determined each male's mating behavior profile by observing the behavior of a single male in the presence of a receptive female. We found that P. velifera showed evidence of an alternate male mating strategy, with small males generally performing only gonopodial thrusts (forced insemination attempts) towards receptive females, while large males performed courtship displays as well as gonopodial thrusts. Males of P. petenensis performed similar rates of courtship displays and gonopodial thrusts regardless of body length. Little variation existed among populations of P. velifera in mating behaviors, while males from different populations of P. petenensis showed population‐specific average rates of each mating behavior. Population differences in P. petenensis may be driven, in part, by its occurrence in more variable habitats than those occupied by P. velifera. Variation among individuals in the mating repertoire of P. velifera, but not P. petenensis, suggests that the greater range of variation in male size at maturity, as well as considerably stronger allometry between dorsal fin size and body length, may explain why males of P. velifera show the greatest degree of expression of alternate male mating behaviors when compared to other sailfin species. These results also suggest an important role of morphological polymorphisms in predicting the expression of alternate male mating behaviors.
Association of single nucleotide polymorphism of chicken uncoupling protein gene with muscle and fatness traits
Authors: Liu S. , Wang S.Z. , Li Z.H. , Li H. 
Published: July 2007

SummaryUncoupling proteins (UCPs) are in the mitochondrial inner membrane and belong to the transporter family. The biological function of UCPs is regulating discharge of proton gradient generated by the respiratory chain. As a result, the production of ATP is diminished, and dissipative heat is yielded. The present study was designed to investigate the association of UCP gene with chicken growth and body composition traits. The ninth generation of the broiler lines divergently selected for abdominal fat was used as a research population. Primers for UCP gene were designed from chicken genomic sequence. A single‐nucleotide polymorphism, in the exon3 (T1316C) of UCP gene was detected by the polymerase chain reaction and restriction fragment polymorphism (PCR‐RFLP) method. The UCP polymorphism was associated with muscle and fatness traits, such as pectoralis minor weight and abdominal fat weight. The results indicated that UCP gene could be a candidate locus or linked to a major gene which affects muscle and fatness traits in chicken.
Effect of dietary phosphorus and its interaction with genetic background on global gene expression in porcine muscle
Authors: Qu A. , Rothschild M.F. , Stahl C.H. 
Published: July 2007

SummaryEnvironmental concerns and costs associated with dietary phosphorus (P) supplementation have lead to attempts to minimize the amount of P added to swine diets. In addition to its requirement for bone growth, dietary P is also necessary for muscular growth. To examine the effects of genetic background and dietary P on global gene expression in the muscle of young pigs, we utilized muscle tissue from 36 gilts sired from two different sire lines. These animals were fed either a P adequate, P deficient or P repletion diets for 14 days and showed differences in growth performance and bone integrity in response to the interaction of genetic background and dietary P. Total RNA from the loin muscle of these animals was obtained for microarray analysis. Significant differences (p < 0.01) in gene expression were seen based on the effect of sire line (339 genes), dietary P (18 genes) and the interaction between sire line and dietary P (31 genes). The microarray data were validated by semi‐quantitative real‐time PCR. These results support our hypothesis that genetic background and dietary P treatment can affect the homeorhetic control of P metabolism in pigs. Genes identified as differentially expressed in this study may be excellent candidate genes for additional work to elucidate genotype specific P requirements as well as to identify a genetic background that can maintain superior growth in a more environmentally friendly manner.
Impact of milk pricing system on the economic response to selection on milk components
Authors: Wolfová M. , Wolf J. , Přibyl J. 
Published: July 2007

SummaryThe impact of various milk pricing systems on the economic weights and the resulting selection responses for milk yield and fat and protein contents in Holstein and Czech Fleckvieh were investigated. The calculations were done for the situations with and without quotas on milk yield and fat content. There was a substantial influence of the milk pricing system on the selection response. The use of index weights based on a ‘wrong’ pricing system reduced the total economic selection response by up to 51% of the selection response expected for an index based on the ‘correct’ pricing system. Financial losses in the selection response were greater with quotas than without quotas. Higher losses were also calculated for Holstein compared with Czech Fleckvieh. Incorrect assumptions on the output limitation (absence or presence of milk quotas) led only to minor reductions in the total selection response (mostly <2%) if the other parameters were correct. The results indicate that customized subindices for milk production traits would increase farmers’ profit from sire selection when selling milk on the basis of different pricing systems.
Analysis of genetic diversity and conservation priorities for six north Ethiopian cattle breeds
Authors: Zerabruk M. , Bennewitz J. , Kantanen J. , Olsaker I. , Vangen O. 
Published: July 2007

SummaryGenetic diversity and conservation potential of six indigenous cattle breeds of north Ethiopia was analysed based on 20 microsatellite markers using core set methods. Expected future diversity (assuming assigned extinction probabilities are valid for the next 20–50 years) were 0.988 ± 0.011 and 0.980 ± 0.010 with expected loss of diversity estimated at 0.02% and 0.74% of current level for the Maximum Variance Total (MVT) and Maximum Variance Offspring (MVO) core sets, respectively. Even though all breeds have contributed to current diversity levels, the Afar and Abergelle breeds only contributed 51% and 62% to the MVT and MVO core sets, respectively, while the Raya breed contributed only 6% and 1.5% to the MVT and MVO core set diversities, respectively. Moreover, prioritizing the six north Ethiopian cattle breeds using the conservation potential obtained from the MVT core set method seems reasonable considering the origin and migration histories of the breeds. Our results suggest that the total current genetic diversity of these breeds can be sufficiently maintained by designing a conservation strategy based on conservation potential of each breed from the MVT core set so that priority is given to lowering the extinction probabilities of breeds with high conservation potential to zero.
Testing the equivalence of different ovine PrP genotypes for estimated breeding values
Authors: Parada A. , Arana A. , Alfonso L. 
Published: July 2007

SummaryIn this study we applied equivalence testing methods to prove the absence of differences in genetic values of ewes with different PrP genotypes. In particular, the milk production genetic value equivalence of ARR ovine prion protein (PrP) genotypes was analysed. There is no scientific evidence implying that the performances and genetic values of different PrP genotypes will be different, but it is interesting to confirm that the performance of one genotype is indistinguishable from another before starting a genetic scrapie control programme. Genotyping was performed on 204 ewes from a Spanish population of Lacaune breed. Ewes were sampled from the lower and upper tails for the distribution of estimated breeding value (EBV) for standardized lactation. The conditional probability that the number of ARR alleles contained in the group of higher EBV was larger than that found in the group of lower EBV was found to be in the interval between the true value (1/2) and two different pre‐specified bounds (0.1 and 0.2). The results evidence the equivalence of ARR PrP genotypes for milk production EBV, and lead to the conclusion that the average genetic values for milk production of Lacaune flocks considered will not be affected by the selection of ewe carriers of resistance scrapie alleles (p < 0.05).
Study on the association of BoLA‐DRB3.2 alleles with clinical mastitis in Norwegian Red cows
Authors: Kulberg S. , Heringstad B. , Guttersrud O.A. , Olsaker I. 
Published: July 2007

SummaryGenotyping of bovine leucocyte antigen DRB3.2 (BoLA‐DRB3.2) in a total of 523 Norwegian Red (NR) cows from two groups selected for high protein yield and low clinical mastitis, respectively, identified 27 previously reported BoLA‐DRB3.2 alleles across the groups. Significant differences in BoLA‐DRB3.2 allele frequencies were found between the selection groups. Alleles *13, *18, *22 and *27 had a significantly higher frequency in cows selected for low clinical mastitis, while alleles *3, *9, *11 and *26 had a higher frequency in cows selected for high protein yield. Associations between BoLA‐DRB3.2 alleles and clinical mastitis were analysed based on mastitis data from 741 072 first‐lactation NR cows, of which 452 were genotyped. Alleles *22 and *26 were found to be associated with increased clinical mastitis, while alleles *7, *11, *18 and *24 had a favourable effect on mastitis resistance. Contradictory results from different studies investigating associations between BoLA‐DRB3.2 alleles and mastitis indicate that future studies should focus on associations of mastitis with BoLA haplotypes rather than with single BoLA genes.
Evaluation of canine heat‐shock transcription factor 4 as a candidate for primary cataracts in English Cocker Spaniels and wire‐haired Kromfohrlanders
Authors: Engelhardt A. , Wöhlke A. , Distl O. 
Published: July 2007

SummaryCanine heat‐shock transcription factor 4 (HSF4) was evaluated as a candidate for primary cataracts in English Cocker Spaniels (ECS) and wire‐haired Kromfohrlanders (KFL). We sequenced exon 9 and its flanking regions of the HSF4 gene in ECS and KFL but were not able to detect a previously reported insertion mutation associated with primary cataracts in Staffordshire Bull Terriers and Boston Terriers. Another single nucleotide polymorphism (LOC489766:g.3243A>G) in intron 9 was identified and included in linkage and association tests together with two flanking microsatellites. Linkage and association tests with primary cataracts in ECS and KFL were not significant. Therefore, we could not verify that the mutation in exon 9 of canine HSF4 gene is causative for primary cataracts in ECS and wire‐haired KFL.
Characterization of polymorphisms of transferrin receptor and their association with susceptibility to ETEC F4ab/ac in pigs
Authors: Wang Y. , Ren J. , Lan L. , Yan X. , Huang X. , Peng Q. , Tang H. , Zhang B. , Ji H. , Huang L. 
Published: July 2007

SummaryDiarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc × Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371‐bp amplicons containing the complete coding region of TFRC using RNA of eight full‐sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc × Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus.
SNP discovery, expression and association analysis for the SDHD gene in pigs
Authors: Guimaraes S.E.F. , Rothschild M.F. , Ciobanu D. , Stahl C.H. , Lonergan S.M. 
Published: July 2007

SummaryThe SDHD gene was examined for single nucleotide polymorphisms (SNP) as well as for expression changes in the Longissimus dorsi muscle of commercial pigs with different potential for growth. Three SNPs, including one previously described in the coding region and two new ones in the 3′‐UTR, were found. The normalized expression of SDHD was correlated with growth, meat quality and sensory traits (p < 0.05). For the commercial pigs used in this study, as well as a Berkshire × Yorkshire resource population, the SNPs have been associated (p < 0.05) with: growth, carcass composition, meat quality and sensory traits. Despite the fact that the described SNPs were not significantly associated with the normalized expression values, the SDHD SNPs and expression were associated with growth and meat quality traits in pigs.