Why Man Penis Boneless ?
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One of the latest findings and important to know is how this evolutionary process has made some modern human body parts are different from their ancestors.
The experts in the United States recently revealed the reason why humans have large brains and were blessed with a vital tool that soft and spineless. According to the theory of the scientists, this is apparently caused by the loss of a few chains or sequences of DNA during the passage of evolution.
In a report published in the journal Nature, scientists from Stanford University showed the difference between humans and mammals closest relatives, the chimpanzees. They said this change is the result of loss of DNA sequences from about 6 million years ago.
The women in this world seems to be thankful to these changes because of DNA that "wasted" that exist that can trigger the penis becomes reinforced. DNA is also suspected of making chimps now have a penis that "sharp" and reinforced.
Co-author of the report, Professor David Kingsley, of the Howard Hughes Medical Institute at Stanford University, said that the loss of bone in the penis may be one factor why people are now developing a monogamous relationship.
Meanwhile, chimpanzees and other mammals creature believed to use by eliminating the vital reproductive sperm competition.
"Organisms that have a penis bone in general have a couple of competitive systems," said Professor Kingsley.
"Females will promote when they thrive and they can only have sex around ovulation. The period of ovulation in humans is hidden and the women in our species can have sex for a long time. The loss of bone in the penis is a whole series of related bond long-term rather than a momentary encounter, "said Kingsley.
In their research, the experts compared the genes of modern humans and chimps and monkey. The experts identified 510 segments of DNA are missing in humans, but the very existence of the chimpanzee and monkey. The research also uses computer analysis to identify loss of DNA sequences that terkluster around specific genes.
"We see more changes in the vicinity of genes involved in steroid hormone signal transmission," said Professor Kingsley.
According to investigators, the changes are also more visible in the vicinity of the genes involved in nervous system development.
The study was also conducted using rats in the laboratory to look for two sequences of DNA. The first relates to the androgen receptor gene, while the second relates to GADD45g genes that suppress the growth of cells. Research on rats that found the first gene associated with genital, while GADD45g genes associated with brain growth.
Kingsley said, the loss of genes, which make the brain cells can grow under control, may contribute to the growth of larger brains. However, he stated that the loss of the DNA structure is only one factor in the development of a new offspring.
Source : Tk
Posted by Anggo82
on Monday, April 11, 2011. Filed under