The lion's closest relatives are the other Panthera species: the tiger, snow leopard, jaguar, and leopard.
Results of phylogenetic studies published in 20 indicated that the jaguar and the lion belong to one sister group, which diverged about 2.06 million years ago.
Results indicated that lions form three phylogeographic groups, one each in North Africa and Asia, in Central Africa and in Southern Africa.
Samples of 53 lions, both wild and captive individuals, from 15 countries were used for phylogenetic analysis.
Lion populations are untenable outside designated protected areas.
Although the cause of the decline is not fully understood, habitat loss and conflicts with humans are the greatest causes of concern.
Lions have been kept in menageries since the time of the Roman Empire, and have been a key species sought for exhibition in zoos over the world since the late 18th century.
Zoos are cooperating worldwide in breeding programs for the endangered Asiatic lions.
It is possibly extinct in Mauritania, Mali, Ghana, Guinea, Côte d'Ivoire, Gambia, Guinea-Bissau, Sierra Leone and Togo.
Results showed little genetic diversity between lions from Asia, West and Central Africa, whereas lions from East Africa were genetically closer to lions from Southern Africa.
Results of another phylogeographic study indicate that southeastern Ethiopia, western Somalia and northern Kenya are genetic admixture regions between lions from Central Africa and Southern Africa, and that lions in the northern part of Central Africa are genetically closer to lions in North and West Africa, and those in the southern part of Central Africa closer to lions in Southern Africa.
Nonetheless, they might carry genes that are extinct in the wild, and might be therefore important to maintain overall genetic variability of the lion. In North Africa, lions are regionally extinct in the wild due to excessive hunting; the last known Barbary lion was killed in Morocco in 1942.
In 2017, the Cat Classification Task Force of the Cat Specialist Group assigned the lion populations in Asia and West, Central and North Africa to P. Small groups of lions may have survived until the 1960s.