Name: Frank
Status: Educator
Grade: Other
Location: Outside U.S.
Country: Canada
Date: October 2008
Question:
Regarding human evolution: A chromosomal fusion event occured
in our (human) evolutionary history that brought our number down to 23
pairs (vs 24 in other apes). How would this type of mutation (I believe
its termed a Robertsonian translocation) get passed on?
Replies:
I don't believe it is an example of Robertsonian translocation because that is
when two acrocentric chromosomes break apart at the centromeres and two of the
nonhomologous arms fuse together. My understanding of the fusion that occurred
in primates to make the human diploid number was when two whole chromosomes
fused. The p arms of both are fused. The evidence for this is that there is
telomeric DNA internally, as if the ends of two chromsomes fused at their
tips. There are also two centromeres, although one of them has accumulated
enough mutations that it doesn't serve as a second centromere any more.
You can read more at:
http://en.wikipedia.org/wiki/Chromosome_2_(human)
vanhoeck
I must be missing something here. A fused chromosome would get passed on the
same way any other chromosome that confers a selective advantage on the
organism would.
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.
