Explain the relationships anywhere between crossing-over and you will genetic adaptation
Into the mitosis anaphase begins by section of centromeres, in meiosis it doesn’t exist until the anaphase away from the next division (not revealed)
The fresh new Relation out of Mitosis and you can Meiosis (considering Darlington). Remember that the newest chromosomes is actually double on their first appearance in the mitosis, not regarding the first (leptotene) stage out of meiotic prophase. They few when you look at the zygotene, beginning to feel twice (split) when you look at the pachytene, and are also double during the last values from meiotic prophase (diplotene and diakinesis). The Mechanics Of your own CHROMOSOMES II5 proof in support of telosynapsis try adduced on thickness from persisted groups off chromosomes at meiotic metaphase in certain bacteria (chiefly Oenothera), however, various other a lot more sufficient explana- tion is now able to be given for it (p. Darlington try the first ever to recommend that if for example the parasynaptic interpre- tation are adopted, all differences when considering meiosis and you can mitosis can, with the aid of few hypotheses, getting deduced from the fresh difference in the latest singleness otherwise doubleness of the prophase posts.
The guy recommended that homologous chromosomes, or rather homologous chromonemata, appeal one another in the pairs. That it appeal are fulfilled from inside the mitotic prophase, but not in early meiotic prophase, where in fact the chromosomes is located at earliest single, and will simply match the interest of the coming together with her from inside the zygotene pairing. (閱讀全文…)