As new types in nature? According to the theory of evolution, one possibility to do this in a rather simplified form it looks like this: population of animals or plants become geographically isolated — separated, for example, a river that changes direction. Next, two separate groups to accumulate genetic differences, and over time their DNA would become so different that they are considered different species. But there is also a more rare form called “backup” or “reinforcement” of species (reinforcement). And at this point his vengeance is watching a group of scientists.
Researchers from the University of Michigan (USA) studied in Mexico habitat of two species of monkeys-Howler monkeys — Howler monkeys and black Howler monkeys Columbia. The fact that the isolation and “difference” their descendants will not be able to interbreed with each other. Immediately there was a pretty interesting situation. About 3 million years ago, apes lived in this territory, break it up, but about 10 thousand years ago once again began to contact. The result is now in the “hybrid zone” 2 species of monkeys coexist and hybridize with each other, and the population of the offspring of hybrids is quite large.
“We observed patterns in genetic data, indicating that hybridization plays a direct role in the completion of the speciation process by strengthening the genetic differences between species. This result is particularly noteworthy because empirical evidence of its existence are extremely rare, especially when we can examine them at the genetic level.” — said one of the study’s authors Marcella Baiz in an interview with the journal Molecular Ecology.
Natural selection, preventing formation of hybrids, enhances reproductive isolation by increasing genetic differences. This process is called reinforcement. Although this hypothesis exists for more than a century of empirical data confirming its existence, is not enough.
If reinforcement works to prevent hybridization and to strengthen reproductive isolation, the genetic differences between the two species in a hybrid zone should be greater than genetic differences between apes these two species living on both sides of the hybrid zone. This was studied by the group of researchers. Despite the fact that the hybrid monkeys very much, most of them die before reaching sexual maturity or are not able to reproduce. When the DNA of the pups revealed that most viable are individuals whose DNA is less similar to the DNA of another species. That is, in fact, those individuals who belong to different species and are not involved in interspecific hybridization.
And you can develop gaining new information. It is full in our news channel in Yandex Zen.