All therian mammals have a similar XY/XX sex-determination system except for a dozen species. The African pygmy mouse, Mus minutoides, harbors an unconventional system in which all males are XY, and ...

Proceedings of the Academy of Natural Sciences of Philadelphia, Vol. 140, No. 1 (1988), pp. 220-239 (20 pages) Widespread hybridogenetic interspecies hybrids (Rana ridibunda × R. lessonae) reproduce ...

Scientists found six sex chromosomes in the Odorrana swinhoana frog species endemic in Taiwan, giving new insights into how complex XY systems evolve. The finding suggested that translocation -- a ...

Modern genetics reveals that over 50 genes across many chromosomes—not just X and Y—govern sex development. The term “sex ...

Based on the biology lessons back in our schooldays, we know that XX means female, and XY means male. In mammals, these constellations of sex chromosomes determine whether an individual becomes a ...

Many animals use a special pair of chromosomes to determine their sex during development, but how did this system evolve? Where did these chromosomes come from and how do they change over time?

Nautiloids—a lineage of ancient, externally-shelled cephalopods that diverged from their octopus and squid relatives over 400 million years ago—once dominated our oceans. Today, this living fossil is ...

The O. swinhoana frog species is the first vertebrate known to retain descendant genes that now determine sex in mammals, birds, and fishes inherited from a common ancestor. Scientists found six sex ...