Dosage compensation in Z/W chromosome systems

Fri Jan 8 08:12:04 EST 1993

>>    I am looking for recent work on dosage compensation in birds,
>>snakes and other species with Z/W chromosome systems. The best references I
>>have are Johnson and Turner (1979) Heredity 43, 71-77 and
>>         Baverstock et al., (1982) Nature 296, 763-766.
>>    I will be checking the Science Citation Index to see who is citing these
>>papers now but there may be some papers I miss. Can anyone help?
>>                                             Sincerely,
>>                                                       Don Forsdyke
>Uh, could you enlighten me as to why Z/W systems need dosage compensation
>-- I thought the Z/W meant that the two chromosomes contained the
>same genes except for the sex-determination factor.

   In mammals the X is 5% of the genome and they have dosage compensation. In
birds the Z is 10% of the genome, so they would appear even more in need of
compensation. In birds the Z is like the Y chromosome, degenerate, having lost
the majority of its genes. The heterogametic sex is essentially haploid
(hemizygous) for the sex chromosomes.

               Sincerely, Don Forsdyke

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