Homogenized Genes |
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| This
figure represents a 12 thousand base pair section of repetitive rDNA in
the species Drosophila melanogaster. The black portions are transcribed
and then assembled into ribosomes, the protein making machinery of the
cell. The white portion labeled NTS contains a 240 base pair repeated
segment that numbers approximately 10 within each rDNA segment. The repeated
sequences of 240 base pairs are identical to each other within the rDNA
segment, and in every rDNA segment in the fly, and in every individual
fly of D. melanogaster tested. In the sibling species Drosophila mauritiana, this 240 base pair segment differs in sequence from the corresponding Drosophila melanogaster segment. But again this 240 base pair segment is identical to every other repeat in the Drosophila mauritiana genome in every individual tested. The same could be said for the 5 other Drosophila sibling species. Dover attributes this phenomenon to unequal crossing-over, gene conversion, and slippage. |