タバタ厚賢 From inside the mitosis anaphase begins from the office of centromeres, in meiosis this doesn’t exist up until the anaphase out of next department (not found)
New Relation regarding Mitosis and Meiosis (predicated on Darlington). Note that brand new chromosomes are twice at the their very first looks into the mitosis, although not about earliest (leptotene) stage from meiotic prophase. It partners inside zygotene, begin to become double (split) in the pachytene, and are usually double during the last amount out-of meiotic prophase (diplotene and diakinesis). New Auto mechanics Of your CHROMOSOMES II5 evidence meant for telosynapsis try adduced regarding occurrence of continuing bands away from chromosomes in the meiotic metaphase in certain bacteria (chiefly Oenothera), but several other way more high enough explana- tion can be given because of it (p. Darlington try the first ever to suggest that if the parasynaptic interpre- tation was adopted, the differences when considering meiosis and you can mitosis is, by using not many hypotheses, getting deduced on new difference in the new singleness otherwise doubleness of the prophase posts.
The guy recommended you to homologous chromosomes, or rather homologous chromonemata, interest each other for the sets. Which appeal are met in mitotic prophase, not during the early meiotic prophase, where chromosomes is at very first solitary, and can just satisfy the attraction because of the future with her inside the zygotene combining. For the meiosis, the latest spHtting of the chromosomes, which happens in the latest interphase before an excellent mitotic division, does not takes place till pachytene if chromosomes are actually related into the pairs. They ergo produces a set of four related posts and these break down into the diplotene loops, becoming held together of the changes out-of lover in the chiasmata.
Hence Darlington supposed the spUtting regarding a good chromosome when preparing for another mitotic division happens in the fresh interphase prior to that division, hence the fresh singleness of your own meiotic chromo- somes is born simply to the fact they begin condensation and you will con- grip with the department up until the breaking keeps occurred. That it hypo- thesis is named the Precocity Theory. A change in the straightforward precocity theory has been proposed by the Huskins,^ which accepts Darhngton’s hypotheses that the differences between the two sort off section are caused by the new repulsion anywhere between sets of chromonemata and you will appeal ranging from single chromonemata, however, rejects Darlington’s account of your own source of singleness regarding the newest meiotic chromosomes inside prophase. Predicated on Huskins, the fresh new splitting of the chromosomes for example department happens through the the earlier office, forming a therefore-named tertiary split that triggers the fresh chromo- specific sets in the mitotic metaphase becoming actually quadripartite, the individuals within meiotic metaphase octopartite government.
New losing aside of five posts is actually proof you to regardless of if a couple homologous chromosomes attention both, you to group of homologous chromonemata Online Bewerte mein Date Dating repels several other similar couple
During the interphase ahead of meiosis, this tertiary spUt have to be allowed to be destroyed in certain means, simply to be restored on pachytene; in about the fresh new diakinesis stage they ^ Cf. Huskins and you may Smith 1934. Il6 An overview of Progressive Genetics is succeeded from the other broke up towards the division which uses next meiotic division. The two concepts render a bit other profile out of anaphase separa- tion. Centered on Darlington, the first breakup of your chromo- somes inside anaphase is in mitosis as a result of the department regarding this new centromeres at this time as well as in meiosis to an increased repulsion amongst the centromeres and therefore now starts to beat the newest pushes holding the new chromosomes together with her at chiasmata. Centered on Huskins, in addition, the newest breakup of mitotic chromosomes is actually analogous with the formation off diplotene loops ; it’s due to the formation of the new tertiary separated which transforms the new matched mitotic chromosomes towards the a couple of mutually repelling matched threads.