Biology of Reproduction, Vol 21, 575-582, Copyright © 1979 by Society for the Study of Reproduction

Gonosome-Autosome Translocations in the Domestic Fowl: Their Effect upon Male Fertility and Semen Characteristics

¹ Department of Dairy Science, The Ohio State University and The Ohio Agricultural Research and Development Center, Columbus, Ohio 43210

Spermatogenic dysfunction, characterized by varying degrees of spermatogenic arrest and enhanced production of morphologically abnormal spermatozoa, has been reported in mammals heterozygous for certain chromosome translocations, especially those involving an X chromosome. However, the effects of chromosome translocations on spermatogenesis and fertility in organisms with male homogameity, such as birds, remain largely unknown. To investigate possible spermatogenic anomalies owing to translocation heterozygosity, we used domestic fowl singly or doubly heterozygous for 2 different Z-autosome translocations. The analysis of 10 different semen characteristics in groups of cockerels bearing the translocations revealed no significant difference from a control group bearing the normal chromosome complement. Estimates of the fertilizing ability of spermatozoa collected from cockerels within each karyotypic group also were not significantly different. These results indicate that 1) neither the fertilizing ability nor the phenotype of spermatozoa is adversely affected by their chromosome complement and 2) the spermatogenic process in the domestic fowl is not arrested by meiotic barriers which, as reported for mammals, act to prevent the transmission of certain chromosome translocations. Results obtained from the domestic fowl are discussed in terms of proposed genetic mechanisms for spermatogenic dysfunction in mammalian translocation heterozygotes.

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ACKNOWLEDGMENTS The authors thank Dr. W. R. Gomes for his continued interest and helpful comments on the manuscript and Miss Sandra L. Woolard for excellent technical assistance.