Freethought & Rationalism Archive

MrDarwin · 06-19-2003, 08:14 AM

Hey, doesn't anybody here read the news besides me? From Sciencedaily.com:

Birds Do It. Bugs Do It. But Why Don't We? (and original news release)

Peez · 06-19-2003, 08:22 AM

From the linked article:

Quote:

To test their idea, Zhang's team zeroed in on a human gene called TRP2, which makes an ion channel that is unique to the pheromone signaling pathway. They found that in humans and Old World primates, this gene suffered a mutation just over 23 million years ago that rendered it dysfunctional. But because we could use color vision for mating, it didn't hurt us. In turn, the pheromone receptor genes that rely on this ion channel fell into disuse, and in a random fashion, mutated to a dysfunctional state because they haven't experienced any pressure from natural selection. Zhang calls this process "evolutionary deterioration."

Oolon, add that to your list. I wonder if humans and chimps share the exact same mutation.

Peez

P.S. Thanks for the link, Mr. D.

lpetrich · 06-19-2003, 10:48 AM

This "evolutionary deterioration" is known from elsewhere:

Blind cave fish often have eyes.

Parasitic plants that have lost photosynthesis sometimes continue to grow leaves; I once saw a picture of such a plant with white leaves.

The parasite of crabs Sacculina is descended from barnacles, but it only resembles a barnacle in its larval phase, before it grows into a host and gets the shape that inspired its name. Likewise, barnacles themselves are very short on abdominal segments compared to other crustaceans.

Parasitic and symbiotic bacteria often have much-reduced metabolic capabilities as compared to free-living ones.

Etc.

MrDarwin · 06-19-2003, 12:09 PM

Not to mention that parasitic plants like Epifagus that are extremely specialized to obtain all their nutrients from other plants, and thus do not need to photosynthesize, do not produce chlorophyll but often have chloroplasts and chloroplast DNA with the genes relating to photosynthesis disabled (i.e., they have become pseudogenes).

RufusAtticus · 06-19-2003, 02:09 PM

Not to mention the fact that humans have hundreds (!!!) of pseudogenes for ofactory sensors.

06-19-2003, 08:14 AM	#1
MrDarwin Veteran Member Join Date: May 2001 Location: Washington, DC Posts: 4,140	Pheromones, genes, and primate evolution Hey, doesn't anybody here read the news besides me? From Sciencedaily.com: Birds Do It. Bugs Do It. But Why Don't We? (and original news release)

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06-19-2003, 10:48 AM	#3
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	This "evolutionary deterioration" is known from elsewhere: Blind cave fish often have eyes. Parasitic plants that have lost photosynthesis sometimes continue to grow leaves; I once saw a picture of such a plant with white leaves. The parasite of crabs Sacculina is descended from barnacles, but it only resembles a barnacle in its larval phase, before it grows into a host and gets the shape that inspired its name. Likewise, barnacles themselves are very short on abdominal segments compared to other crustaceans. Parasitic and symbiotic bacteria often have much-reduced metabolic capabilities as compared to free-living ones. Etc.

06-19-2003, 12:09 PM	#4
MrDarwin Veteran Member Join Date: May 2001 Location: Washington, DC Posts: 4,140	Not to mention that parasitic plants like Epifagus that are extremely specialized to obtain all their nutrients from other plants, and thus do not need to photosynthesize, do not produce chlorophyll but often have chloroplasts and chloroplast DNA with the genes relating to photosynthesis disabled (i.e., they have become pseudogenes).

06-19-2003, 02:09 PM	#5
RufusAtticus Veteran Member Join Date: Nov 2001 Location: NCSU Posts: 5,853	Not to mention the fact that humans have hundreds (!!!) of pseudogenes for ofactory sensors.

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