Figure 1.

PCR products for the autosomal, Z-linked, and W-linked loci. (a) One per cent agarose gel showing a single band of approximately 550 bp for autosomal gene NCK2 and Z-linked gene VCAN in a female and a male of the blue-footed booby. (b) Same as (a) for autosomal gene NCK2 and Z-linked gene DMRT1 in a female and a male of the magnificent frigatebird. (c) The same as in (a) but for the W-linked gene RICTOR in five females and five males of the blue-footed boobies. (d) Same as in (a) but for the W-linked gene APC1 in three females and three males of the magnificent frigatebird; in this case, we observed minor cross-amplification of the Z gametologue in males.