The W chromosome sex chromosome
is found in all bird
s and certain other animal
s where the female
is the heterogametic
sex. The W chromosome
causes the individual to become female
in such species. It is part of the WZ set of sex chromosomes, where the female has one W chromosome and one Z chromosome
, and the male
has two Z chromosomes.
The information in this writeup was taken from the science dictionary at http://biotech.icmb.utexas.edu/; I oversaw the development of the dictionary (the website was mothballed in 1998) and I believe I wrote the entry this is based on.