A comparison of flow cytometry and the polymerase chain reaction as sexing techniques for the Wood Thrush

Abstract

Abstract Gender identification is important in demographic studies of bird populations but is difficult with monomorphic bird species. Flow cytometry, a method which estimates differences in DNA content in erythrocyte nuclei, is one potential sexing method. In another sexing method, differences between the autosomal and sex-linked (W) copies of the chromo-helicase-DNA binding (CHD) gene can be determined using the polymerase chain reaction (PCR). Frozen blood samples collected during the breeding season from known-sex adults and juvenile birds were used to test the applicability of flow cytometry and PCR as sexing methods for the Wood Thrush (Hylocichla mustelina). With flow cytometry, 86% of 14 known adults were definitively and correctly sexed. PCR correctly sexed 100% of 11 known adults. Of the 18 juveniles, 15 were sorted definitively by flow cytometry: 14 as male and one as female. PCR sexed the same 18 juveniles as 11 males and seven females, including the three juveniles that were unclassified by f...