SEX IDENTIFICATION IN BIRDS USING 2 CHD GENES

In theory, birds should control the sex ratio of the offspring they pr oduce. In practice, we have very limited evidence to support this idea because of our difficulty in sexing nestling birds. In addition, exti nction is facing an increasing number of birds. Our ability to help in cludes captive breeding which, again, is difficult if male and female adults cannot be recognized. Here we describe the discovery of a W-lin ked gene in the Great tit (Parus major). It is named CHD-W (chromodoma in-helicase-DNA-binding protein W-linked), it is highly conserved and it is W-chromosome linked in a range of bird species. These birds also possess a second, non-W-linked CHD gene (CHD-NW). A single, simple po lymerase chain reaction technique based on both genes can be used to i dentify the sex in a wide variety of birds.