‘Virgin births’ for giant lizards

From BBC News:Lizard_1

Scientists report of two cases where female Komodo dragons have produced offspring without male contact.

Tests revealed their eggs had developed without being fertilised by sperm – a process called parthenogenesis, the team wrote in the journal Nature. Lizards could make use of the ability to reproduce asexually when, for example, a lone female was washed up alone on an island with no males to breed with.

Because of the genetics of this process, her children would always be male. This is because Komodo dragons have W and Z chromosomes – females have one W and one Z, males have two Ws. The egg from the female carries one chromosome, either a W or Z, and when parthenogenesis takes place, either the W or Z is duplicated. This leads to eggs which are WW and ZZ. ZZ eggs are not viable, but WW eggs are, and lead to male baby Komodo dragons.

More here.