title: Does local adaptation cause high population differentiation of Silene latifolia Y chromosomes?
abstract: Natural selection can reduce the effective population size of the nonrecombining Y chromosome, whereas local adaptation of Y-linked genes can increase the population divergence and overall intra-species polymorphism of Y-linked sequences. The plant Silene latifolia evolved a Y chromosome relatively recently, and most known X-linked genes have functional Y homologues, making the species interesting for comparisons of X- and Y-linked diversity and subdivision. Y-linked genes show higher population differentiation, compared to X-linked genes, and this might be maintained by local adaptation in Y-linked genes (or low sequence diversity). Here we attempt to test between these causes by investigating DNA polymorphism and population differentiation using a larger set of Y-linked and X-linked S. latifolia genes (than used previously), and show that net sequence divergence for Y-linked sequences (measured by D(a) , also known as δ) is low, and not consistently higher than X-linked genes. This does not support local adaptation, instead, the higher values of differentiation measures for the Y-linked genes probably result largely from reduced total variation on the Y chromosome, which in turn reflect deterministic processes lowering effective population sizes of evolving Y-chromosomes.
authors: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, United Kingdom. graham.muir@plants.ox.ac.uk
authors: Graham
authors: G
authors: Muir
authors: Roberta
authors: R
authors: Bergero
authors: Deborah
authors: D
authors: Charlesworth
authors: Dmitry A
authors: DA
authors: Filatov
mesh_terms: D000222:Adaptation, Physiological; D032461:Chromosomes, Plant; D005060:Europe; D017343:Genes, Plant; D006239:Haplotypes; D011110:Polymorphism, Genetic; D011157:Population Dynamics; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D012730:Sex Chromosomes; D029751:Silene / Q000235:genetics* / Q000502:physiology