Month: September 2022

ISOLATION. "One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation." https://lnkd.in/eBtiTBE View in LinkedIn

SPECIATION DRIVER. "These data provide strong evidence that sexual selection is driving behavioural isolation and speciation, supporting sexual selection as a cause for speciation in the wild." https://lnkd.in/eBtiTBE View in LinkedIn

EVOLUTION PATH. "If many adaptive changes occur when a chromosome in a co-sexual species evolves into a sex chromosome, this would suggest that trade-offs are common; that is, that these changes were maladaptive in co-sexual ancestors." https://lnkd.in/exrSaeb View in LinkedIn

POPULATION IMPACT. "In genome regions with suppressed recombination, selection acting on either advantageous or disadvantageous mutations in the region affects all linked variants. This effectively restricts the size of the population, compared with the rest of the species’ genome, because some genotypes fail to reproduce. The effective population size can be considerably reduced for a Y chromosome that still carries many functional sequences." https://lnkd.in/exrSaeb View in LinkedIn

SMALL POPULATION AND MUTATIONS. "The reduced effective population size allows deleterious mutations in functional sequences to increase in frequency in the population, or become fixed, causing deterioration of the sequences." https://lnkd.in/exrSaeb View in LinkedIn

PURIFYING SELECTION. "In plants, however, few deleterious changes may occur in Y-linked alleles, because a high proportion of genes are expressed in the haploid pollen, and, if these genes have important functions during pollination, they may experience strong purifying selection against sequence changes that impair their functions." https://lnkd.in/exrSaeb View in LinkedIn

ACCUMULATION OF JUMPING GENES. "A reduced effective population size not only allows deleterious substitutions to occur, it also allows accumulation of transposable element (TE) insertions, which are mostly deleterious." https://lnkd.in/exrSaeb View in LinkedIn

SEX CHROMOSOMES AND TRANSPOSABLE ELEMENTS. "TE insertions may therefore accumulate in non-recombining Y chromosome regions, or the loss of gene functions in these regions (see below) may reduce selection against such insertions." (TE = transposable elements). https://lnkd.in/exrSaeb View in LinkedIn

BULKING SEQUENCES. "The accumulation of TEs and other repetitive sequences is probably a major contributor to the tendency for plant Y chromosomes to be larger than their X homologues." (TE = transposable elements) https://lnkd.in/exrSaeb View in LinkedIn

X VS Y CHROMOSOMES. "TE accumulation may occur on the X as well as the Y chromosome. In dioecious plants so far studied genetically, recombination occurs in both sexes, as in mammals. The X chromosome thus has a lower recombination frequency than the autosomes, because X chromosomes recombine only in females." (TE = transposable elements). https://lnkd.in/exrSaeb View in LinkedIn