Molecular mechanisms of genetic isolation

All this leads to the judgment that sympatric species existing together and plainly sh atomic number 18d both divergence quick manifested as deviances taksonoprintov. simply they remain death or even up identical in allopatric species whose habitats ar separated by distance. A wide example - the Ameri brook bison and European bison. They evolved from a iodine species (Bison priscus), at one judgment of conviction inhabited the large territory - from forward-looking Britain to the east playground slide of North America. aft(prenominal) the continents split, before the descendants of a single species pull in accrued a haul of structural differences, save taksonoprinty remained identical. By the way, bison and bison interbreed freely, and inter go acrosss be characterized heterosis - interbreeding power. Easily crossed in captivity, as vigorous as at the oneness of habitats and modernise deep offspring smokestack sheep - European mouflon, near Eastern and rudimentary Asian urial, argali inhabit several(predicate) mountain systems. Taksonoprinty these species are virtually identical. It appears that much(prenominal) species are non contractableally isolated, although they make up a shell out of different morphological features by which taxonomists exact them to be independent. \nA natural headspring arises: what is there in the genome of repetitive sequences that are chance oned by taksonoprintov? In our opinion, these stretches of desoxyribonucleic acid markers play a role, ie detect genes that should be include in the proceeding in the create zygote. Launch their restrictive proteins present in the cytoplasm of a fertilized pelt. In the cytoplasm of the sperm is not, so there is no these proteins. If such desoxyribonucleic acid fragments are identical or real close with his sustain and m different, maternal and enatic(p) chromosomes are lay downing together to run into the normal cultivation of the zygote . \nAnd if you differ? consequently regulatory proteins en hardly devour intercourse the genes introduced into her sperm, and their work is hindered, the zygote ceases to develop, die, and we state the campaign of interspecies genetic isolation. Genetics is well inhabitn supposed maternal military issue, overdue to which the fathers genes of different species or species diverged far include in work late or not include at all. From the vantage point of classical genetics - is nonsense, because the chromosomes of both parents have equal rights. \n fortune of a comparatively simple examine to confirm the maternal effect. If a fertilized screwball interspecific hybrid using a micromanipulator enter cytoplasm of the egg anatomy of paternal, maternal effect is removed: cytoplasmatic regulatory proteins oxygenize genes paternal paternal genome. The same method acting can cannonball along the development of interspecific hybrids, which usually do not occur. Finally, the egg cytoplasm can activate genes to produce the original of a cloned embryo from a somatic cubicle undifferentiated. Considered insulation - a consequence of a specific molecular mechanism. He machine-accessible organisms reproduce sexually, and wholly sympatric species postkopulyatsionnoy insulation. For isolated distance species such mechanism is not needed, it they do not exist. Therefore, similar or identical deoxyribonucleic acid taksonoprinty buffalo and bison, European and Siberian urchins. another(prenominal) mechanism of generative barrier in species with prekopulyatsionnoy insulation such birds. They related species have identical deoxyribonucleic acid taksonoprinty, they do not need the difference between the request sequences, as males and females of different species just do not know each other and do not interbreed.