AN INTRODUCTION TO MAMMALIAN INTERSPECIFIC HYBRIDS

Haldane's law states that in interspecific hybrids, it is the heteroga metic sex that is likely to be absent, rare, or sterile, In mammals, t here is increasing evidence to suggest that this may be due to the hig h mutation rate of male sex-determining genes on the Y chromosome. The mule, humanity's first successful attempt at genetic engineering, pro vides some support for this concept, Interspecific hybrids may also sh ed new light on the importance of the maternal transmission of mitocho ndrial DNA and the phenomenon of genomic imprinting.