Jenny Graves – Distinguished Professor of Genetics, Los Angeles Trobe University

It’s thought the sibling and sibling (who possess identical genes from their mom not their daddy) developed from an egg fertilised by two various semen during the exact same minute.

The highly uncommon “semi-identical” Australian twins reported the other day will be the consequence of a unusual occasion. It’s thought the sibling and sis (who’ve identical genes from their mom although not their daddy) developed from an egg fertilised by two various semen during the exact same minute.

In people, it is the semen that determines whether an embryo is pushed along a male or female development path. However in wild wild birds, it is one other means around. Eggs will be the factor that is deciding bird intercourse.

There are more fascinating areas of bird intercourse that aren’t distributed to people. Feminine wild birds appear to have some ability to get a grip on the intercourse of the chicks. And periodically a bird that is feminine on a single part and male in the other is produced – like in current reports for this cardinal in the us.

X and Y, Z and W chromosomes

Just what exactly is it about bird chromosomes that produces bird intercourse therefore different from individual intercourse?

In people, cells in females have actually two copies of a big, gene-rich chromosome called X. Male cells get one X, and a small Y chromosome. […]