Monthly Archives: August 2009

A single mutation lead to human bipedalism?

Walking Monkey: Could human posture be due to a single mutation?

Walking Monkey: Could human posture be due to a single mutation?

Interesting indeed but I was not able to find the source or any other reports on this monkey. Take it with a grain of salt. Scientists have recently published a report in PNAS that indicates that bipedal humans came from tree living apes. Could it be that our tree living ancestor had a mutation (like Natasha, the Israeli monkey) that allowed them to become bipedals. Being bipedal gave them benefit in the flat sub-Saharan Africa as they had vision much farther down and also could throw weapons such as spears better. This may have lead to the rise of the Homo? Of course this is a speculation but not entirely untrue.

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Filed under Evolution, Human Evolution

Malarial parasite came from chimps!

“The conventional wisdom on malaria is that this is a disease that has been in humans since the dawn of humanity,” said infectious disease expert Nathan Wolfe of Stanford University, who co-authored the paper published Monday in the Proceedings of the National Academy of Sciences. “In fact, what we found was really quite surprising to us: There is a tremendous diversity of these parasites in chimpanzees, and it’s a diversity that completely encompasses a much more limited diversity in human malaria.”

“There’s only one way to interpret that finding,” Wolfe said. “Namely, that this is a chimpanzee parasite that had jumped over to human populations.”

According to Ed Yong, plasmodium protein EBA-175 binds to GYPA on the surface of the red blood cells. A gene, CMAH, crippled in humans and active in chimps renders chimps susceptible to P. reichinowi but not humans. However, a different EBA-175, possibly unique to P.falciparum can infect human RBC. This may explain why humans are susceptible to P. falciparum.

Such theories of differential evolutionary trajectories of the same gene in chimp and human is not new rendering humans susceptible to a particular disease is not new. Scientists working with trim5alpha have suggested the same for HIV. Interestingly for Malaria though, there is another species of plasmodium, P. vivax, that according to the malarial species tree, is in a completely different branch and infects humans, although without being as detrimental as its counterpart evolved from the chimps.

So, it is very important to understand whether all human malarial parasites use the same pathway to infect RBCs. May be it is already known and I am unaware about it…anyone knows?

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Filed under Evolution, My Life My Thoughts

Evolutionary ‘flaws’ and wonders of evolution

I thought it was pretty funny to read the Wired’s recently posted 10 Worst Evolutionary Designs. However, when I read the comments posted by the users, I was really shocked to find out that many scrutinized the author.

My take is, it was an article trying to educate the readers about imperfect world. Therefore, the article conveyed only one message to me: life could not have been designed by God as it exist, in its imperfect form. Although, I did not like the use of “design” in the title. Evolution is not a designed process. It is a hit and trial process rather than design. Among a group of organisms, one has a certain beneficial mutation that renders it more fit. Thus, it can reproduce at higher rates than others and the gene gets fixed in the population. Thus, for every ‘flaw’ that the author pointed out, there is a reason or basis of adaptation. However, it is true that many things in nature are not perfect and that is what is the beauty of evolution!

P.S. To those readers who criticized the author of the above article stating that each organism is best adapted for its surrounding therefore they are as good as they are: a new paper in scientific journal PNAS by Alfaro et al. indicates that there are evolutionary winners and losers; based on species richness, i.e., the diversity in species within a family, one can calculate success rates of various animal lineages. Based on their results, the most successful animals are modern birds, coral fish, and mammals.

My curiosity made me compile a list of organisms with interesting characteristics or interesting evolutionary past. Some of them are listed below.

Evolution1Evol6Evolution2Evol3Evol7Evol4whaleconch evolutionPolar bear

 

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Filed under Evolution, My Life My Thoughts

My forgotten dreamcatcher

You know about the things that we get and forget right? We do that all the time. I bought a dreamcatcher once in a Mexican arts and craft store where I went to shorten my wrist-watch’s metal band. I did not know what a ‘dreamcatcher’ was at that time. According to Wikipedia,

According to Terri J. Andrews, “Only good dreams would be allowed to filter through . . . Bad dreams would stay in the net, disappearing with the light of day.”[4] Good dreams would pass through and slide down the feathers to the sleeper.

The store operator told me…or I understood it so that a dreamcatcher brings your dreams come true…so, I bought one… it was made out of leather, red leather on the outside, yellow on the inside with one long white feather and another short one on top of it. It looked beautiful. I bought it for its aesthetic appeal rather than its associations with dreams.

In any case, I placed it above the computer of my laptop dock on my desk and it probably fell behind the screen and I forgot about it. At that time, I was a recent graduate with shameful grades and struggling finances and therefore a low self-esteem of all times. In those days I used to dream about having my own project, my own publications and going to graduate school…which is where I am today.

Today is my last day at work. As I was cleaning my desk to head out to Africa tomorrow and then to Chicago for my PhD, I found my dreamcatcher behind the computer screen. May be it was there this whole time catching me good dreams and making my dreams come true. I had an option to chug it or take it with me…guess what I did….you guessed it right. Its in the box with “The most valuable things” scribbled on it.

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