[Sympatric Speciation of the Plague Microbe Yersinia pestis: Monohostal Specialization in the Host-Parasite Marmot-Flea (Marmota sibirica-Oropsylla silantiewi) System].

An ecological scenario of the origin of the plague microbe that is interpreted in the light of modern Darwinism (synthetic theory of evolution) is presented. It is shown that the plague microbe emerged from a clone of the psychrophilic saprozoonotic pseudotuberculosis microbe Yersinia pseudotuberculosis O:1b in the mountain steppe landscapes of Central Asia in the Sartan time, 22000-15000 years ago, in the monohostal Mongolian marmot (Marmota sibirica)-flea (Oropsylla silantiewi) host-parasite system. It was noted that the evolutionary process described corresponds to the sympatric form of speciation by transition ofthe clone of migrant founders to a new, already-existing ecological niche. It was established that monohostal specialization of the plague microbe was made possible due to heterothermia (5-37 degrees C) of marmots in the hibernation period. The factors of the speciation process--isolation, the struggle for existence, and natural selection--were analyzed.