Bactrian camel
The Bactrian camel and the dromedary often interbreed to produce fertile offspring. Where the ranges of the two species overlap, such as in northern Punjab, Iran and Afghanistan, the phenotypic differences between them tend to decrease as a result of extensive crossbreeding between them. The fertility of their hybrid has given rise to speculation that the Bactrian camel and the dromedary should be merged into a single species with two varieties. However, a 1994 analysis of the mitochondrial cytochrome b gene revealed that the species display 10.3% divergence in their sequences.