Tipping points in the dynamics of speciation. The human Y chromosome: overlapping DNA clones spanning the euchromatic region. Page Manager: Johan [dot] Nilsson [at] biol [dot] lu [dot] se. Sex limited inheritance in Drosophila. Journal List Proc Biol Sci v. Close karyological kinship between the reptilian suborder Serpentes and the class Aves.
While one of D.
For example, rapid divergence was facilitated by increased numbers of selected loci and low migration. Sex was not always determined by DNA. Lucchesi JC. Other authors have recently reviewed this literature [ 15 ], so we will not dwell on it in detail here.
Sex-biased gene expression at homomorphic sex chromosomes in emus and its implication for sex chromosome evolution.
The fusion of a second autosome led to the formation of the current structure of the turquoise killifish sex chromosome. However, we cannot exclude that we could not detect positive selection at the QTL regions due to statistical power or that the populations used in this study and those used for the QTL analysis had a different genetic architecture of lifespan.
In general, males tend to have lower rates of recombination than females during meiosis and this pattern is independent of male or female heterogamety PLoS Biol 8: e This ratio is undefined for genes without any information about polymorphic or substituted sites. Anolis sex chromosomes are derived from a single ancestral pair.
Sex chromosome dosage compensation After recombination has been halted between the sex chromosomes, the non-recombining Y or W chromosome decays Whole chromosome painting reveals independent origin of sex chromosomes in closely related forms of a fish species.
It's currently unclear whether widespread sexual antagonism usually precedes the evolution of sex chromosomes or not [ 96 ], so one solution is to measure sexually antagonistic variation in species with a combination of sex determination systems, such as the snow skink Niveoscincus ocellatus , where sex is temperature-dependent in the lowland but genetically determined in the highland [ 97 ].
This means that many of the first discoveries of the properties of sex chromosomes have been in model organisms with highly diverged sex chromosomes such as Drosophila or humans, and this has of course biased our view of the diversity of sex chromosomes in nature [ 1 ].
The evolution of dosage compensation could perhaps be investigated via artificially induced aneuploidy followed by experimental evolution. The evolution of dominance. Human spermatozoa: the future of sex. But when warm-blooded mammals with internal reproduction arose, sex determination by temperature became problematic.