3,497,444 research outputs found
Complex Adaptations and the Evolution of Evolvability
No full textComplex Adaptations and the Evolution of Evolvability
+representation problem: "evolvability critically depends on the way genetic variation maps onto phenotypic variation"
+Evidence that phenotypic variation is under genetic control: canalization; mutant phenotypes often show more variation than the wild phenotype (see p.7) "the variability of the traits itself can evolve"
+cites Halder1995: Drosophila eyeless - out-of-place eye production can be triggered by a single signal
+"genotype-phenotype map underlying theme of: genetic canalization, developmental constraints, biological versatility, developmental dissociability, morphological integration" and more
+genotype-phenotype map evolves, main selective forces: epistatic mutations, creation of new genes
+"Variability needs to be distinguished from variation" (variability: potential to vary [*dispositional* concept, not actual state but expected development of a phenotypic trait in response to genetic and environmental influences] - variation: actually realized differences between individuals)
+cites Levinton1988: generation of variability needs to be studied
+Evolution of complex adaptations requires a match between the functional relationships of the phenotypic characters and their genetic representation - cites Riedl1975: "If the epigenetic regulation of gene expression 'imitates' the functional organization of the traits then the improvement by mutation and selection is facilitated" (helps when sexual recombination, p.11)
+cites Wright1968 "Pleiotropy cannot be wholly universal" - how limit:
modularity, interaction mainly short range, less frequent between members of different complexes
+evolution of modularity: origin of differentiated animals dominated by parcellation / detachment (opposed to integration of distinct parts)
but where shall we put delimitations??
Evolution of Dosage Compensation in Anolis carolinensis, a Reptile with XX/XY Chromosomal Sex Determination
Full text linkabstract: In species with highly heteromorphic sex chromosomes, the degradation of one of the sex chromosomes will result in unequal gene expression between the sexes (e.g. between XX females and XY males) and between the sex chromosomes and the autosomes. Dosage compensation is a process whereby genes on the sex chromosomes achieve equal gene expression. We compared genome-wide levels of transcription between males and females, and between the X chromosome and the autosomes in the green anole, Anolis carolinensis. We present evidence for dosage compensation between the sexes, and between the sex chromosomes and the autosomes. When dividing the X chromosome into regions based on linkage groups, we discovered that genes in the first reported X-linked region, anole linkage group b (LGb), exhibit complete dosage compensation, although the rest of the X-linked genes exhibit incomplete dosage compensation. Our data further suggest that the mechanism of this dosage compensation is upregulation of the X chromosome in males. We report that approximately 10% of coding genes, most of which are on the autosomes, are differentially expressed between males and females. In addition, genes on the X chromosome exhibited higher ratios of nonsynonymous to synonymous substitution than autosomal genes, consistent with the fast-X effect. Our results from the green anole add an additional observation of dosage compensation in a species with XX/XY sex determination.The final version of this article, as published in Genome Biology and Evolution, can be viewed online at: https://academic.oup.com/gbe/article/9/1/231/2680052/Evolution-of-Dosage-Compensation-in-Anoli
Chemoreceptor Evolution in Hymenoptera and Its Implications for the Evolution of Eusociality
Full text linkabstract: Eusocial insects, mostly Hymenoptera, have evolved unique colonial lifestyles that rely on the perception of social context mainly through pheromones, and chemoreceptors are hypothesized to have played important adaptive roles in the evolution of sociality. However, because chemoreceptor repertoires have been characterized in few social insects and their solitary relatives, a comprehensive examination of this hypothesis has not been possible. Here, we annotate ∼3,000 odorant and gustatory receptors in recently sequenced Hymenoptera genomes and systematically compare >4,000 chemoreceptors from 13 hymenopterans, representing one solitary lineage (wasps) and three independently evolved eusocial lineages (ants and two bees). We observe a strong general tendency for chemoreceptors to expand in Hymenoptera, whereas the specifics of gene gains/losses are highly diverse between lineages. We also find more frequent positive selection on chemoreceptors in a facultative eusocial bee and in the common ancestor of ants compared with solitary wasps. Our results suggest that the frequent expansions of chemoreceptors have facilitated the transition to eusociality. Divergent expression patterns of odorant receptors between honeybee and ants further indicate differential roles of chemoreceptors in parallel trajectories of social evolution.The final version of this article, as published in Genome Biology and Evolution, can be viewed online at: https://academic.oup.com/gbe/article/7/8/2407/558582/Chemoreceptor-Evolution-in-Hymenoptera-and-It
Evolution of altitudinal migration in passerines is linked to diet
No full textBird migration is typically associated with a latitudinal movement from north to south and vice versa. However, many bird species migrate seasonally with an upslope or downslope movement in a process termed altitudinal migration. Globally, 830 of the 6,579 Passeriformes species are considered altitudinal migrants and this pattern has emerged multiple times across 77 families of this order. Recent work has indicated an association between altitudinal migration and diet, but none have looked at diet as a potential evolutionary driver. Here, we investigated potential evolutionary drivers of altitudinal migration in passerines around the world by using phylogenetic comparative methods. We tested for evolutionary associations between altitudinal migration and foraging guild and primary habitat preference in passerines species worldwide. Our results indicate that foraging guild is evolutionarily associated with altitudinal migration, but this relationship varies across zoogeographical regions. In the Nearctic, herbivorous and omnivorous species are associated with altitudinal migration, while only omnivorous species are associated with altitudinal migration in the Palearctic. Habitat was not strongly linked to the evolution of altitudinal migration. While our results point to diet as a potentially important driver of altitudinal migration, the evolution
of this behavior is complex and certainly driven by multiple factors. Altitudinal migration varies in its use (for breeding or molting), within a species, population, and even at the individual level. As such, the evolution of altitudinal migration is likely
driven by an ensemble of factors, but this study provides a beginning framework for understanding the evolution of this complex behavior.articlespublishedphylogenetic comparative analysisbird movementevolutionforaging guildPasseriforme
cancer-evolution/Evolutionary_analysis_of_coexpression_modules: First release
No full text<p>Code matches the version of manuscript submitted to Genome Biology in April 2024.</p>
The evolution and population diversity of human-specific segmental duplications
Full text linkSegmental duplications contribute to human evolution, adaptation and genomic instability but are often poorly characterized. We investigate the evolution, genetic variation and coding potential of human-specific segmental duplications (HSDs). We identify 218 HSDs based on analysis of 322 deeply sequenced archaic and contemporary hominid genomes. We sequence 550 human and nonhuman primate genomic clones to reconstruct the evolution of the largest, most complex regions with protein-coding potential (N = 80 genes from 33 gene families). We show that HSDs are non-randomly organized, associate preferentially with ancestral ape duplications termed 'core duplicons' and evolved primarily in an interspersed inverted orientation. In addition to Homo sapiens-specific gene expansions (such as TCAF1/TCAF2), we highlight ten gene families (for example, ARHGAP11B and SRGAP2C) where copy number never returns to the ancestral state, there is evidence of mRNA splicing and no common gene-disruptive mutations are observed in the general population. Such duplicates are candidates for the evolution of human-specific adaptive traits
Welcome to the Journal of Evolution and Health
No full textWelcome to the first issue of the Journal of Evolution and Health! The Journal of Evolution and Health is the peer-reviewed, open-access journal of the Ancestral Health Society, a community of scientists, healthcare professionals, and laypersons who collaborate to understand health challenges from an evolutionary perspective
Big and Slow: Phylogenetic estimates of molecular evolution in baleen whales (Suborder Mysticeti).
No full textPublished in a leading journal of molecular evolutionary, this article presents the largest databases available to date of mitochondrial and nuclear intron sequences to estimate the ‘neutral’ rate of molecular evolution in the largest species of animals ever to have lived, the baleen whales. The results demonstrated, the despite the rapid morphological divergence of whales from their a terrestrial ancestors, their underlying rate of molecular evolution is the lowest measured for any mammal. Times Cited: 12 (from Web of Science). I initiated the study with a grant from the Marsden Fund and directed the laboratory analyses and assembly of the sequence database. I supervised the first author, my postdoctoral fellow, and assisted in writing the manuscript
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