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I could swear that in the past I had covered news that the minute genetic and massive phenotypic differences between humans and chimpanzees are due to the alternative splicing. But I can’t seem to find the post at all… there maybe a slight chance I didn’t post about it but I’m pretty sure I did cause this is the kind of science that I love to gobble up. Oh well… I guess it all doesn’t really matter because University of Toronto researchers, Benjamin Blencowe and John Calarco, have discovered significant differences in the way genetic material of humans and chimpanzees are spliced to create proteins.

Splicing ProcessHere’s a very brief introduction into splicing… Splicing is a type of modification of a gene that happens after a sequence is transcribed. What actually happens is that introns of pre-messenger RNA (pre-mRNA) are removed and exons of it are joined. I remember exons as expressed sequences and introns as intervening sequences.

This process produces the mature messenger RNA (mRNA), which then undergoes translation and ultimately becomes a protein. In many cases, the splicing process can create a range of unique proteins by varying the exon composition of the same messenger RNA. This phenomenon is then called alternative splicing. The illustration to your right documents what’s happening.

Blencowe comments,

“It’s clear that humans are very different from chimpanzees on several levels, but we wanted to find out if it could be the splicing process that accounts for some of these fundamental differences. The surprising thing we found was that six to eight per cent of the alternative splicing events we looked at were showing differences, which is quite significant. And those genes that showed differences in splicing are associated with a range of important processes, including susceptibility to certain diseases.”

He and his team have published their findings in the Journal of Genes and Development. The paper, “Global analysis of alternative splicing differences between humans and chimpanzees” can be summarized in one sentences, alternative splicing process differs significantly between humans and chimpanzees and is one of the main reasons as to why humans and chimpanzees are so different phenotypically but so similar genetically.

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