The multiple sex chromosomes of platypus and echidna are not completely identical and several share homology with the avian Z.

ABSTRACT:

Background

Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has five X and five Y chromosomes, no SRY, and DMRT1 on an X chromosome. In order to investigate monotreme sex chromosome evolution, we performed a comparative study of platypus and echidna by chromosome painting and comparative gene mapping.

Results

Chromosome painting reveals a meiotic ch

SUBMITTER: Rens W 

PROVIDER: S-EPMC2258203 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature