Research overview: the genetics of ligers, tigons and other big-cat hybrids

Crosses between lions and tigers in captivity produce ligers and tigons, hybrids notable for unusual growth patterns, with ligers often growing larger than either parent. This overview surveys the biology behind these phenotypes, including the hypothesis of genomic imprinting and disrupted growth-regulating gene dosage when species with different reproductive strategies are crossed. It discusses the general infertility of male hybrids versus occasional female fertility, the health problems associated with such crosses, and the ethical and conservation objections to deliberately breeding them. The survey frames big-cat hybrids as a window into imprinting and reproductive isolation rather than a conservation tool.