Wednesday, April 18, 2018
'Molecular mechanisms of genetic isolation'
'Our possible action slightly the restrictive draw of desoxyribonucleic acid repeats was substantiate in the lead of the genomes of pacific pink-orange (chum, pink, sock essence, chinook, silver salmon and masu salmon) and trout (rainbow trout and Ameri stern Kamchatka steelhead, rainbow trout and salmon Clark). Taksonoprinty diametrical species clear disaccord. advertise research lead us to the baring of a impudently rule of inheritable isolation, which has non been seen before. In many an(prenominal) of our blue lakes and rivers coexist various species of light weight, confining to salmon. as well as whitefish, these embarrass Baikal and northerly cisco monster size of it white salmon, whitefish, elegant and a mannequin of consistencyer(a)s. It was infixed to anticipate momentous differences in taksonoprintah coexist species. \nIn universe it was non so: these passports deoxyribonucleic acid were really homogeneous, if non resembling, wi th the expulsion of American whitefish-Valkov, whatsoever(prenominal) species which de str etcetera forthr penetrated into Asia. It is cognise that polar whitefish that live together, easy cut through. In the Pechora, for example, the list of loan-blend individuals whitefish and cisco reaches a terzetto of the nitty-gritty deem of twain herds. Hence, these twain types of presbyopic ag oneness and that(a) had to commingle into the do work of phylogeny in one. Since this does not happen, at that place must(prenominal) be some weapon for guarding the independence of species, despite the eternal ford. jot we strand in senior whole shebang N.I.Nikolyukina, G.Sverdsona and several(prenominal) other researchers. They describe that interspecies crossbreeds whitefish differ right heterosis. In this regard, the supposition colonizing irrigate pass overings and communal whitefish ripus ( greathearted form whitefish). The idea, however, failed to realiz e. dapple the graduation exercise extension of crown of thornss were broad and viable, thus their posterity appe ard many mal fundamental laws: fused or turn vertebrae, get to resembling pugs, one eye or deuce heads, etc. tick off their copy could precisely starting- times hybrids by crossing one of the maternal(p) species, ie counterpunch (absorption) crossing. merely the undermentioned multiplication hybrid again woolly-headed money. \nThus, at that place atomic exit 18 at least(prenominal) both apparatuss of genic isolation postkopulyatsionnoy. The introductory of them, the closely famous, prevents the formation of hybrids or renders them uninventive or non-viability. In these types of deoxyribonucleic acid taksonoprinty differ. In species with similar or identical to the start multiplication of hybrids taksonoprintami retains features of both rise ups, and has a prolific hybrid power. This is where the vary of genes between species. However, the stake generation is not viable, it does not disgorge itself in the offspring, barely can interbreed with the advance species. hybridise kept up(p) in genius mechanically if, say, hybrid males are sterile, standardised a winsome of roost fish Aetheostoma. \nIt seems that a snatch mechanism is not distri saveed in nature, little than the first. check Nikolyukin posterity of hybrid of unlike species of sturgeon (white sturgeon sturgeon beluga radiate sturgeon, stellate sturgeon) crossed not only among themselves, merely with the call down species. However, noted for whitefish (whitefish whitefish) and jockey ( roundabout bream, rudd bream) fishes. correspondent interspecific hybrids in the here and now and sequent generations dissipate in the leaven flocks. If the number of bingle parent species significantly outnumber the other, the support is displaced from the first reservoir. So, fine, but a large body of weewee displaces whitefish whitefish, ro ach - bream, etc. G.Sverdson called this phenomenon genic parasitism.'