To elucidate the strain preference in donor and recipient for the production of W-bearing sperm, mixed-sex germline chimeric chickens were produced. The combination of donor and recipient was White Leghorn (WL) and Barred Plymouth Rock (BPR), and vice versa. Four sets of mixed-sex chimeras that had the male phenotype at sexual maturity were subjected to analysis: group 1, a female WL donor and a male BPR recipient; group 2, a male WL donor and a female BPR recipient; group 3, a female BPR donor and a male WL recipient; group 4, a male BPR donor and a female WL recipient. The mean number of W-bearing sperm detected by in situ hybridization among 10000 sperm observed was 135, 158, 26 and 71 in groups 1, 2, 3 and 4, respectively. The number in group I was significantly higher than that of group 3 (P < 0.05). And the number in group 2 was significantly higher than those of groups 3 and 4 (P < 0.05). It is suggested that the combination of a WL donor and a BPR recipient produced W-bearing sperm more efficiently than the reverse combination. (C) 2002 Elsevier Science Inc. All rights reserved.
