Usually, in the nature of an individual are divided by gender into two floors, with the exception of hermaphrodites, and some of the features of some of reproduction in living beings. However, half a century ago, scientists had discovered an interesting feature of the ciliate Tetrahymena thermophila.
It turned out that this little micro-organism has seven (!) Equality, but to date the mechanism of inheritance of sex in these creatures remained unexplored. But scientists from the University of California, seriously address this issue, were able to determine which pairs of genes specific to each gender ciliates. As suggested by Eduardo Orias, project manager, all of these genes were once common "ancestor", but in the process of evolution has occurred divergence of gene pathways, and the vapors are determinants.
In ciliates pyriformis has a pair of cores: large and small somatic sex. Hereditary information is naturally located in the small core and it acts as an ovary or testis. In the process of crossing between the sexes ciliates the formation of a new pair of nuclei with "kneaded" genetic material of two ciliates. In this case, the sexual core contains two inactive (incomplete) of a pair of genes, and the large - one full of activity that will fit in only one of the sexes.
Once the new kernel is formed, the somatic nucleus, "give" a small core of the missing portions of genes, and then the floor will get any advantage over the others. The remaining unclaimed pair of genes eliminated from the genome. In total, the process can be represented as roulette, in which there are seven sectors, while only coincidence determines coincidence of the two sexes nature and selection of the dominant ones. Control of the process is carried out by molecular apparatus that makes the "re-programming" of genes.
The researchers believe that the study of the process of this device will help in studying the mechanism of recombination of genes in humans. A infusorians such sexual diversity is necessary in order to under adverse conditions for one or two sexual reproduction pyriformis was not under threat.