Recent theoretical and experimental models have revealed the role played by evolution during species spread, and in particular have questioned the influence of genetic drift at range edges. By investigating the spread of an aquatic invader in patchy habitats, we quantified genetic drift and explored its consequences for genetic diversity and fitness. We examined the interplay of gene flow and genetic drift in 36 populations of the red swamp crayfish, Procambarus clarkii, in a relatively recently invaded wetland area (30 years, Brière, northwest France). Despite the small spatial scale of our study (15 km ), populations were highly structured according to the strong barrier of land surfaces and revealed a clear pattern of colonization through watercourses. Isolated populations exhibited small effective sizes and low dispersal rates that depended on water connectivity, suggesting that genetic drift dominated in the evolution of allele frequencies in these populations. We also observed a significant decrease in the genetic diversity of isolated populations over only a 2-year period, but failed to demonstrate an associated fitness cost using fluctuating asymmetry. This study documents the possible strong influence of genetic drift during the spread of a species, and such findings provide critical insights into the current context of profound rearrangements in species distributions due to global change.
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http://dx.doi.org/10.1111/mec.15238 | DOI Listing |
Mol Ecol Resour
January 2025
Department of Animal Science, University of California Davis, Davis, California, USA.
We introduce a new software program, MaxTemp, that increases precision of the temporal method for estimating effective population size (N) in genetic monitoring programs, which are increasingly used to systematically track changes in global biodiversity. Scientists and managers are typically most interested in N for individual generations, either to match with single-generation estimates of census size (N) or to evaluate consequences of specific management actions or environmental events. Systematically sampling every generation produces a time series of single-generation estimates of temporal F ( , which can then be used to estimate N; however, these estimates have relatively low precision because each reflects just a single episode of genetic drift.
View Article and Find Full Text PDFCancers (Basel)
December 2024
Statistical Genetics Research Group, Institute of Medical Biometry, Heidelberg University, Im Neuenheimer Feld 130.3, 69120 Heidelberg, Germany.
Latin Americans have a rich genetic make-up that translates into heterogeneous fractions of the autosomal genome in runs of homozygosity (F) and heterogeneous types and proportions of indigenous American ancestry. While autozygosity has been linked to several human diseases, very little is known about the relationship between inbreeding, genetic ancestry, and cancer risk in Latin Americans. Chile has one of the highest incidences of gallbladder cancer (GBC) in the world, and we investigated the association between inbreeding, GBC, gallstone disease (GSD), and body mass index (BMI) in 4029 genetically admixed Chileans.
View Article and Find Full Text PDFis the causative agent of the venereal disease trichomoniasis which infects men and women globally and is associated with serious outcomes during pregnancy and cancers of the human reproductive tract. Trichomonads parasitize a range of hosts in addition to humans including birds, livestock, and domesticated animals. Recent genetic analysis of trichomonads recovered from columbid birds has provided evidence that these parasite species undergo frequent host-switching, and that a current epoch spillover event from columbids likely gave rise to in humans.
View Article and Find Full Text PDFSci Rep
January 2025
Departament de Medicina i Ciències de la Vida, Institut de Biologia Evolutiva (CSIC-UPF), Universitat Pompeu Fabra, Dr. Aiguader 88, Barcelona, 08003, Catalonia, Spain.
Ibiza (Eivissa) is one of the main Balearic Islands in the western Mediterranean. Recent studies have highlighted the genetic distinctiveness of present-day Eivissans within the region and suggested it could be attributed to the genetic drift caused by recent demographic events. Whether this distinctiveness emerged from a differential demographic history, or rather from a bias for sampling in a small geographic region such as Eivissa, remains an open question, together with the understanding of the functional consequences of demography in the island.
View Article and Find Full Text PDFNature
January 2025
Ancient Genomics Laboratory, Francis Crick Institute, London, UK.
Many known and unknown historical events have remained below detection thresholds of genetic studies because subtle ancestry changes are challenging to reconstruct. Methods based on shared haplotypes and rare variants improve power but are not explicitly temporal and have not been possible to adopt in unbiased ancestry models. Here we develop Twigstats, an approach of time-stratified ancestry analysis that can improve statistical power by an order of magnitude by focusing on coalescences in recent times, while remaining unbiased by population-specific drift.
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