Using Random Sequence Primers in the Polymerase Chain Reaction to identify Gender-Specific Genetic Markers in House Wrens

In order to fully understand the biology of asexually reproducing organism, it is essential that one is able to distinguish the males from the females. In determining the gender of monomorphic birds, standard techniques including visual identification, surgery, and karyotyping are impossible or impractical for large-scale studies. A reliable gender identification method that uses genetic markers identified within the DNA would be an asset to the researcher because it would require only a minimal blood sample which could be collected in the field without harming the bird and stored easily for long periods of time. Griffiths and Tiwari (1993) described such a technique based on the generation of RAPD markers (Random Amplified Polymorphic DNA). The use of RAPDs involves the amplification of genomic DNA in the polymerase chain reaction (PCR) using primers of arbitrary oligonucleotide sequence to generate-a range of DNA fragments that can be separated by agarose gel electrophoresis. This study employs this method to generate a reliable sex probe for the house wren (Troglodytes aedon), using RAPDs to isolate female-specific markers from random locations on the W sex chromosome. Results indicate that after extensive manipulation of the Griffiths and Tiwari protocol, consistent PCR amplification of house wren DNA was achieved. However, further research is necessary to find a primer that will yield W specific fragments in large samples of wrens. If successful, the sex probe will be used in future studies of house wren reproductive strategy. Specifically, gender identification information of house wren nestlings will be used to investigate the maternal condition hypothesis