Wednesday, December 28, 2011

Male-female attraction is governed by DNA

Males and females are naturally attracted to each other in the animal world. This is necessary for procreation: while bacteria can replicate themselves asexually, humans and other animals need sexual reproduction between males and females. Research in frogs shows that females are attracted to singing males, if they have an equal number of chromosomes, which are the carriers of our genetic code. This shows that DNA actually decides attraction, though it is not clear whether humans are also affected by DNA matching.

Frog songs
Researchers from the University of Missouri found that different species of frogs slightly differ in the songs they use to attract females. While the song appears to be identical, the speed at which males sing it is slightly different. Females recognize the songs, and are only interested in the songs that they are 'tuned' too. This interesting phenomenon tells us something about how different frog species evolved.

Genetic matching
The difference in songs appeared to match differences in DNA. In their experiments, the scientists found that one of the investigated frog species which sang its love song more slowly has double the amount of chromosomes. We use chromosomes as structures to keep our DNA in a densely packed shape, and us humans possess 23 pairs of them. Because the number of chromosomes in frogs determines their singing capabilities, it appears that our genetic code is actually the underlying matchmaker for these animals.

Nature versus nurture
Richard Dawkins, the famous British biologist, once suggested that we are mere shells for true replicating structures: DNA. Since his famous book in the seventies, we have found proof of how our genes govern our behaviour. A few decades ago, we thought humans can be fully shaped during their life, and genes only play a role in creating the body. Personality or other seemingly psychological factors could not possible be influenced by genes. We now know otherwise. A lot of human characteristics are governed by both genes and environment: that means they play together, and do not exclude each other. Nowadays, we believe there is no nature versus nurture debate; it is actually nature and nurture.

Human attraction
There are a lot of unconsciously determining factors that decide whether two human beings are attracted to each other. Perhaps the most famous are pheromones, which are similar to hormones, but work between people. It is thought that these chemical signals play a role in our sexual orientation. According to a few scientific studies, the male armpit and sweat may be sources for pheromones. It is not known how our genes influence sexual attraction, but it would not be surprising if evolution favoured certain genes to match with each other.

For those interested in frog songs: the source link above has a few samples.

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