These results are presented in the revised manuscript Discussion section. Haplodiploidy is found in insects belonging to Hymenopterasuch as ants and bees. Spermatogenic X inactivation and dosage compensation provide two processes that distinguish the X chromosome from autosomes and male from female fertility.
Most of them code for something other than female anatomical traits. Help Community portal Recent changes Upload file. Email address. These species' sex chromosomes are relatively primitive and unspecialized. Trends Genet. The Quarterly Review of Biology. Unlike the paired autosomes, in which each member normally carries alleles forms of the same genes, the paired sex chromosomes do not carry an identical complement of genetic information.
Concluding remarks The findings reviewed here leave little doubt that the X chromosome plays a special role in speciation. There are many ancestral polymorphisms segregating in these two species see Table 4consistent with incomplete lineage sorting ILS. Thus, we feel that our implementation of G min to detect regions of introgression has been adequately documented to justify these analyses.
C Maximum likelihood phylogenetic trees for the MDox and Dox regions. X-linked loci have generally smaller effective population sizes than autosomal loci and hence lower levels of nucleotide polymorphism. Overall, these findings show that, relative to D. If X-linked drivers are typically silenced by 3 or 4 autosomal suppressors then, assuming a Drosophila -like karyotype, there would be little or no preferential accumulation compound sex chromosomes definition in Irving divergence on the X chromosome: for every X-linked driver fixed, each autosomal arm, on average, would fix a suppressor.
However, there is some evidence that introgressed D. However, as the X chromosome has lower levels of polymorphism within species, the median net divergence D A between species is 0. High-resolution genome-wide dissection of the two rules of speciation in Drosophila.