Biology subjects

Pichkar, Y.

Publications and source records attributed to Pichkar, Y..

4 recordsLinked to original sources

bioRxiv2023

Detecting cultural evolution in a songbird species using community-science data and computational modeling

Song in oscine birds is learned across generations, and aspects of the song-learning process parallel genetic transmission: variation can be introduced into both cultural and genetic traits via copy-error, and both types of traits are subject to drift and selective pressure. Similarly to allele frequencies in population genetics, observing frequencies of birdsong features can improve our understanding of cultural transmission and evolution. Uniquely, community-science databases of birdsong provide rich spatiotemporal data with untapped potential to evaluate cultural evolution in songbirds. Here we use both community-science and field-study recordings of chipping sparrows to examine trends across nearly seven decades of song. We find that some syllable types tend to persist in the population for much longer than others. Persistent songs tend to contain more syllables of shorter duration than songs that were observed across fewer years. To draw inferences about the effects of learning biases on chipping sparrow syllables, we construct a spatially explicit agent-based model of song learning. By comparing our empirical analysis to simulated song distributions using three different song-learning strategies--neutral transmission, conformity bias, and directional selection--we suggest that chipping sparrows are unlikely to select tutors neutrally or with a conformity bias and that they learn their songs with a remarkably low copy-error rate.

evolutionary biology↗

bioRxiv2022

Subtle cultural boundaries reinforce genetic structure in England

Genes and languages both contain signatures of human history. Genetics and culture have each been shown to track population movements and demographic history. Complicating this picture, cultural traits may themselves influence the ways in which people interact with one another. For example, cultural differences can produce barriers to gene flow if they cause groups of people to differentiate themselves from one another. However, the degree of cultural difference necessary and the magnitude of these effects on gene flow remain unknown. In particular, language differences may limit population mixing, and we focus on whether subtle, dialect-level linguistic differences have influenced genetic population structure, likely by affecting mating preferences. Here, we analyze spatially dense linguistic and genetic data to examine whether the intensity of differences between and within dialects in England are associated with high genetic rates of change. We find that genetic variation and dialect markers have similar spatial distributions on a country-wide scale, and become less distinct as the scale of smaller administrative units such as counties. This covariation, combined with the absence of geographic barriers that could coordinate cultural and genetic differentiation, suggests that some dialect-level linguistic boundaries have influenced the genetic population structure in England.

evolutionary biology↗

bioRxiv2021

Genetic structure correlates with ethnolinguistic diversity in eastern and southern Africa

African populations are the most diverse in the world yet are sorely underrepresented in medical genetics research. Here, we examine the structure of African populations using genetic and comprehensive multigenerational ethnolinguistic data from the Neuropsychiatric Genetics of African Populations-Psychosis study (NeuroGAP-Psychosis) consisting of 900 individuals from Ethiopia, Kenya, South Africa, and Uganda. We find that self-reported language classifications meaningfully tag underlying genetic variation that would be missed with consideration of geography alone, highlighting the importance of culture in shaping genetic diversity. Leveraging our uniquely rich multi-generational ethnolinguistic metadata, we track language transmission through the pedigree, observing the disappearance of several languages in our cohort as well as notable shifts in frequency over three generations. We find suggestive evidence for the rate of language transmission in matrilineal groups having been higher than that for patrilineal ones. We highlight both the diversity of variation within the African continent, as well as how within-Africa variation can be informative for broader variant interpretation; many variants appearing rare elsewhere are common in parts of Africa. The work presented here improves the understanding of the spectrum of genetic variation in African populations and highlights the enormous and complex genetic and ethnolinguistic diversity within Africa.

genomics↗

bioRxiv2019

Accounting for diverse evolutionary forces reveals the mosaic nature of selection on genomic regions associated with human preterm birth

Human pregnancy requires the coordinated function of multiple tissues in both mother and fetus and has evolved in concert with major human adaptations. As a result, pregnancy-associated phenotypes and related disorders are genetically complex and have likely been sculpted by diverse evolutionary forces. However, there is no framework to comprehensively evaluate how these traits evolved or to explore the relationship of evolutionary signatures on trait-associated genetic variants to molecular function. Here we develop an approach to test for signatures of diverse evolutionary forces, including multiple types of selection, and apply it to genomic regions associated with spontaneous preterm birth (sPTB), a complex disorder of global health concern. We find that sPTB-associated regions harbor diverse evolutionary signatures including evolutionary sequence conservation (consistent with the action of negative selection), excess population differentiation (local adaptation), accelerated evolution (positive selection), and balanced polymorphism (balancing selection). Furthermore, these genomic regions show diverse functional characteristics which enables us to use evolutionary and molecular lines of evidence to develop hypotheses about how these genomic regions contribute to sPTB risk. In summary, we introduce an approach for inferring the spectrum of evolutionary forces acting on genomic regions associated with complex disorders. When applied to sPTB-associated genomic regions, this approach both improves our understanding of the potential roles of these regions in pathology and illuminates the mosaic nature of evolutionary forces acting on genomic regions associated with sPTB.

evolutionary biology↗