The silkworm Z chromosome is enriched in testis-specific genes. These changes in recombination will cause small, but measurable, effects on both adaptive 74 and background selection. Others will explain the human damage wrought by such a ruling. Annu Rev Genet. If we can confirm that the presence of heteromorphic sex chromosomes accelerates speciation via increasing the rate at which hybrid incompatibility evolves, species selection would be acting on the species-level trait heteromorphic sex chromosomes.
If so, then epigenetics and hybrid incompatibility are even more tightly intertwined. During the same period evidence emerged that male development was accompanied by enhanced growth, both of gonads and whole embryos. Before we knew much about biology, we made social rules to administer sexual diversity.
The idea of a single Y-chromosomal gene responsible for the differentiation of Sertoli cells is giving way to the realization, based on an increasing body of data, that this gene, in plant sex determination and sex chromosomes videos in York with non-Y-chromosomal genes, increases proliferation in the cells in which it is active.
The evolution of dosage compensation.
Many Silene species are gynodioecious and others are hermaphroditic. Once genes have been identified and sequenced, we will be able to estimate how long sex chromosome evolution takes. Wang, J Mol Gen Genet: —
The scientific study of sex determination can be said to have begun in the 17th century with the discovery of spermatozoa, but the origin and function of the "spermatic animalcules" eluded investigators until Nevertheless it took another century and a half before the mammalian egg was actually discovered.
What are the mechanistic consequences of hemizygous sex chromosomes?