rt

Maybe an easy one, but I couldn't find anywhere else to ask about
this:

Do chromatids in M-phase pair up to one centrosome, or does each
chromatid have its own? This is stated both ways in various texts.
Considering that the spindle has to attach somewhere, and that the two
chromatids get pulled apart at anaphase (by the attached microtubule),
I thought that each chromatid had its own centrosome. But I was told
by a bio prof that this is wrong.

The pictures in the Campbell-reece text do diagram one 'dot' in
between the two chromatids, and it's labeled as 'the centrosome.' But
in the adjoining paragraph, they say "the chromatids are attached by
their centrosomes' (plural).

This seemed obvious to me, as the microtubules are attached to
something after the chromatids are detached. If they don't have their
own centrosomes, then what is the microtubule attached to?

References or speculation welcome.

joachim pimiskern

"RT" <rt@spamfree.***> schrieb:

Some discoveries around that:
http://www.newswise.com/articles/view/506202/
http://www.sciencedaily.com/releases/2007/08/070831171603.htm
http://www.sciencenewsdaily.org/story-3843.html
http://www.embl.org/aboutus/news/press/2007/04may07/index.html

Regards,
Joachim

rt

Maybe an easy one, but I couldn't find anywhere else to ask about
this:

Do chromatids in M-phase pair up to one centrosome, or does each
chromatid have its own? This is stated both ways in various texts.
Considering that the spindle has to attach somewhere, and that the two
chromatids get pulled apart at anaphase (by the attached microtubule),
I thought that each chromatid had its own centrosome. But I was told
by a bio prof that this is wrong.

The pictures in the Campbell-reece text do diagram one 'dot' in
between the two chromatids, and it's labeled as 'the centrosome.' But
in the adjoining paragraph, they say "the chromatids are attached by
their centrosomes' (plural).

This seemed obvious to me, as the microtubules are attached to
something after the chromatids are detached. If they don't have their
own centrosomes, then what is the microtubule attached to?

References or speculation welcome.

joachim pimiskern

"RT" <rt@spamfree.***> schrieb:

Some discoveries around that:
http://www.newswise.com/articles/view/506202/
http://www.sciencedaily.com/releases/2007/08/070831171603.htm
http://www.sciencenewsdaily.org/story-3843.html
http://www.embl.org/aboutus/news/press/2007/04may07/index.html

Regards,
Joachim

rt

Thanks for the links, Joachim. Interesting stuff. But I still didn't
see any definitive word on the original question. Though it is stated
one way or the other in several books that I've seen, it sounds like
this is still up in the air.

rt

Thanks for the links, Joachim. Interesting stuff. But I still didn't
see any definitive word on the original question. Though it is stated
one way or the other in several books that I've seen, it sounds like
this is still up in the air.

bob

Are you talking about centrosomes or centromeres?

Centrosomes have "nothing" to do with the process you refer to.

Each chromosome has one centromere. But it is also ok to refer to the
single centromere at metaphase.
bob

bob

Are you talking about centrosomes or centromeres?

Centrosomes have "nothing" to do with the process you refer to.

Each chromosome has one centromere. But it is also ok to refer to the
single centromere at metaphase.
bob

rt

Well, a bit. They attach to centrosomes via microtubules. And that is
where I don't follow how there could be one centromere per
chromosome/chromatid. During anaphase the two chromatids are pulled
apart, presumably by their centromeres. That would seem to indicate
two centromeres? <g>

So there must be two overlayed centromeres, or they divide at some
point? I haven't been able to find detailed info. Thanks, Bob.

rt

Well, a bit. They attach to centrosomes via microtubules. And that is
where I don't follow how there could be one centromere per
chromosome/chromatid. During anaphase the two chromatids are pulled
apart, presumably by their centromeres. That would seem to indicate
two centromeres? <g>

So there must be two overlayed centromeres, or they divide at some
point? I haven't been able to find detailed info. Thanks, Bob.