A lion has 38 chromosomes that are grouped into 19 pairs. Fifteen of these pairs are common in all cat species.
The lion is classified under kingdom animalia, phylum chordata, class mammalia, order carnivora, family felidae and species panthera leo. The two subspecies of panthera leo are commonly known as the African lion and the Asian lion, with only minor genetic distinctions between the two.
Due to the relatively recent diversification of many species, which only occurred 10 to 15 million years ago, scientists have encountered some difficulty in determining the evolutionary process of the felidae, or cat family. The family's karyotype, which pertains to the appearance and number of chromosomes within the cell's nucleus, has been retained throughout the family's phylogenetic development. However, six unique haplotypes, or inheritable DNA variations on the same chromosome, have been discovered in a phylogenetic study conducted in 2005. These polymorphisms resulted in the formation of two clades, a group of lions that roam the eastern savannas and another group that inhabit the western savannas. At least two other groups exist, which are distributed in the southwestern regions and in the Sabi Sands.
The closest relatives of lions are the tigers, which contain the same number of chromosomes as lions. In captivity, the two large cats are often interbred to produce tigons and ligers. The father of a tigon is a tiger while the father of a liger is a lion. These hybrids are known to be fertile.