The Originality of Humans
21/11/11 20:00 Filed in: GenomeWeb Daily Scan
Submitted by S. Pelech - Kinexus on Mon, 11/21/2011 - 20:00.
While there may be human genes that are not expressed in our primate cousins, this does not mean that they are "exclusively human". They may well be present in our more distant ancestors. There are certainly many genes that are defective or missing in humans and present in the other great apes and other mammals, including, for example, those that act in the synthesis of vitamin C. In fact, some of these genes like myosin and Fox P2 genes, due to their defects, may have actually facilitated the development of larger brain size and speech. In general, the brain and testes often show the most diverse patterns of gene expression. This is particularly evident from the analysis of gene expression available on the open-access TranscriptoNET (www.transcriptonet.ca) website produced by Kinexus. Consequently, it is not surprising that the 60 de novo gene identified showed up more frequently in these organs. The concept that the high expression of some of these genes may account for our "greater" intelligence is also questionable. The definition of intelligence is very subjective. The elephant brain is about 3-times larger than humans. We know from human developmental studies that if neurons are not innervated during early development after birth, they undergo apoptosis. Neurons that are not used become lost. It would seem that elephants, and perhaps even more so whales, must be doing a lot more with their brains than we give them credit for.
Link to the original blog post.
While there may be human genes that are not expressed in our primate cousins, this does not mean that they are "exclusively human". They may well be present in our more distant ancestors. There are certainly many genes that are defective or missing in humans and present in the other great apes and other mammals, including, for example, those that act in the synthesis of vitamin C. In fact, some of these genes like myosin and Fox P2 genes, due to their defects, may have actually facilitated the development of larger brain size and speech. In general, the brain and testes often show the most diverse patterns of gene expression. This is particularly evident from the analysis of gene expression available on the open-access TranscriptoNET (www.transcriptonet.ca) website produced by Kinexus. Consequently, it is not surprising that the 60 de novo gene identified showed up more frequently in these organs. The concept that the high expression of some of these genes may account for our "greater" intelligence is also questionable. The definition of intelligence is very subjective. The elephant brain is about 3-times larger than humans. We know from human developmental studies that if neurons are not innervated during early development after birth, they undergo apoptosis. Neurons that are not used become lost. It would seem that elephants, and perhaps even more so whales, must be doing a lot more with their brains than we give them credit for.
Link to the original blog post.