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Improving the reliability of molecular sexing of birds using a W‐specific marker
Author(s) -
SHIZUKA DAIZABURO,
LYON BRUCE E.
Publication year - 2008
Publication title -
molecular ecology resources
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.96
H-Index - 136
eISSN - 1755-0998
pISSN - 1755-098X
DOI - 10.1111/j.1755-0998.2008.02342.x
Subject(s) - sexing , biology , primer (cosmetics) , genetics , w chromosome , evolutionary biology , intron , chromosome , gene , chemistry , organic chemistry , karyotype
Molecular techniques for identifying sex of birds utilize length differences between CHD‐Z and CHD‐W introns, but in some cases these methods can lead to sexing errors. Here we show that an additional W‐specific primer can be used in conjunction with a pre‐existing sexing primer pair to dramatically improve the reliability of molecular sexing methods. We illustrate the approach with American coots ( Fulica americana ), a species with CHD‐Z polymorphism that could not be accurately sexed using traditional methods. We developed a reverse primer GWR2 designed to sit within the intron of the W chromosome and amplify a distinctively small DNA fragment that serves as a W‐specific marker. Analysis of known‐sex individuals indicates that this W‐specific primer provides an efficient and reliable protocol to identify the sex of F. americana . The development of such sex‐specific primers will likely increase the reliability of molecular sexing methods in other birds as well. Comparisons between CHD‐Z alleles of coots and common moorhens ( Gallinula chloropus ) revealed that CHD‐Z polymorphism evolved separately in these two closely related species. We discuss the implications of repeated evolution of CHD‐Z polymorphisms among birds.