WHAT IS A CHROMOSOME

Jim Owens jow at helix.nih.gov
Mon Feb 7 08:50:13 EST 1994


In article <CKoDyn.Ant at ucdavis.edu> , szdbates at chip.ucdavis.edu writes:
>Single piece of DNA (double stranded) = chromatid
>Pair of chromatids = Chromosome.

My biology degree is vintage 1967.  In grad school I converted to
biochemistry and have not kept up much with biology and how she is
taught. E.g., iIn 1967 there were just two Kingdoms of organisms, plant
and animal; now, according to my daugter's 7th grade science text, there
are three more Kingdoms to take care of those troublesome organisms that
were hard to place in the two Kingdom classification.

So now I have a question about this thread:  Has it been proved that
eucaryotic chromatids have just one very, very long molecule of DNA?  The
last I read, in 1978, said this was _assumed_ to be the case, but it was
not proven.  It was considered possible that there could be a series of
long or very long DNA molecules in a chromatid.

Just wondering,

Jim Owens



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