Stories tagged heredity

He can teach you much, but give you nothing: Wait... Is this man even handsome? This IS complicated!
Courtesy monseurlamSorry to break it to you, dudes, but you aren’t just ugly ducklings—you’re just ugly. Or, if you are mirror-melting hot, those good looks are an invention all of your own, so skip the father’s day present, and get yourself something nice.

See, guys and boys, you’re dad may have taught you how to gut a possum, and he might even have given you your first possum-gutting knife, but he didn’t give you the looks that attracted all those hungry eyes at the possum market. He saved those for your sister.

It turns out that men don’t inherit their fathers’ “attractiveness”. Fathers do pass on masculine features to their sons, but there doesn’t seem to be any strong correlation between attractive fathers (or, technically, “hot dads”) and attractive sons. So says the journal Animal Behaviour.

By rating the images of hundreds of males and females, and their respective parents, the recent study hoped to test the theory that women seek out attractive mates to produce sexy male offspring, who will in turn pass on their mother’s genes.

Uh uh. The study found that hot dads didn’t necessarily have hot boys, and that unattractive fathers (or “ug dads”) didn’t necessarily have ug boys. In fact, the study found no evidence of male-to-male attractiveness inheritance at all. So that beautiful bone structure, those sparkling eyes, that indefinable something that makes you so, so foxy… where did that come from? Your mother, perhaps?

Nope, attractiveness doesn’t seem to come from your mom either. It seems that when boys are born, they’re cast out into the Land of Fug to fend for themselves, and if they find a sunny hilltop to build a face on, they have to do it on their own.

Mothers, the study found, do pass on attractiveness to their daughters. And, ironically, so do fathers—hot dads are likely to have attractive daughters. That means that daughters are getting all those good looks funneled into them from both sides! Ooooh, I hate them so much!

It’s like the legend of Puss in Boots, really. The wealthy old miller and his wife (who I believe was some sort of novelty hat heiress) were on their deathbeds at the same time (food poisoning, I believe), and were deciding how to divvy up their vast wealth between their two sons and one daughter. Keep in mind, this was before division was invented, so the two dying parents decided that the fairest thing to do would be to give all their money to the daughter and none to the sons. The daughter lived a long and very happy life, and no more needs to be said about her. One of the sons died more or less on the spot (food poisoning, I believe), and the other grabbed the miller’s cat and did a runner.

The stolen cat may or may not have had a plan for the surviving son’s well-being, but there was no way to tell, because the cat couldn’t speak English, and the son couldn’t speak Cat. So, making the best of what he had, the son forgot to feed the cat until it died, and then took its fur. (And this was clever in itself, because the son was still too poor to afford a knife, and he had to be creative—that’s where the saying “there’s more than one way to skin a cat” comes from.) The son then used the beautiful fur (it was a good cat) to make an attractive fur hat (a skill he learned from his mother), which he sold to a local eccentric. The profits from the sale were then invested in the construction of a new animal shelter/hat factory. The venture proved to be a lucrative one, and it kept the man in stockings and gin for the rest of his life, until he burned the factory down so that his own son couldn’t inherit it.

Do you see the connection? If you replace all references to money in the story with the word “hotness,” the analogy is particularly apt.

Tags : absurd, heredity, attractiveness, hot dads, genetics, sociology, animal behavior, cats, daughters, sons

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For decades, scientists have been growing microbes in their labs and watching them evolve new traits. Most of the changes tend to be simple things, like an increase in size or growth rate.

But Dr. Richard Lenski of Michigan State University (just 2 miles from my house!) recently witnessed a major evolutionary leap--as it was happening. Twenty years ago, he took a colony of E. coli, a common bacteria, and split it into 12 identical populations. He’s been watching ever since to see if the strains evolve in different directions.

A few years ago, one of them did. One of his study strains suddenly evolved the ability to eat citrate, a molecule found in citrus fruits. No other E. coli in the world can do this, not even the other strains in Dr. Lenski’s lab. Even given several extra years and thousands of extra generations, the other strains are still citrate-averse. What’s more, the bacteria evolved this mutation entirely on their own, without any prodding or genetic manipulation from the researchers.

Lenski had saved frozen reference samples of all of his strains at regular intervals. Going back and growing new cultures from these samples, he again finds that only those from one strain ever evolve the citrate-eating habit – and only those sample less than about 10 years old. Lenski figures that some mutation happened around that time in one strain – and one strain only – that would later lead to citrate eating. He and his lab are now working on figuring out exactly what that mutation is.

Tags : evolution, bacteria, E. coli, adaptation, heredity, genetics

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Hypolimnas bolina: Also known as the Great Eggfly or Blue Moon Butterfly. Public domain photo by Comacontro at Wikimedia CommonsScientists have reported witnessing a remarkable and rapid display of evolution through natural selection at work in butterflies in the South Pacific.

Sylvain Charlat and Gregory Hurst along with an international research team stationed in the Samoan Islands observed a huge discrepancy in the ratio of males to females in the Hypolimnas bolina butterfly population. At the beginning of 2006, the scientists noticed that the females on the island of Savii outnumbered the males 99 to 1. It turns out the distorted ratio was caused by the Wolbachia an inherited bacterium which selectively kills the male butterflies before they can hatch. The bacteria are passed down through the mother’s genes.

But by year’s end, Charlat and his colleagues discovered the male population had - within just 10 generations - increased to 39% of the population. The researchers credit the males’ swift recovery to a suppressor gene switching on to counter the bacteria.

"To my knowledge, this is the fastest evolutionary change that has ever been observed," said Charlat, a post-doctoral researcher with joint appointments at the University College London, and University of California, Berkeley. "This study shows that when a population experiences very intense selective pressures, such as an extremely skewed sex ratio, evolution can happen very fast."

Whether the suppressor gene’s appearance was due to a chance mutation within the local population or introduced by migrating Southeast Asian butterflies where it was already present is not yet known. But Charlat and his team hope to pinpoint the cause in the next three years.

"In essence, organisms must evolve or change to stay in the same place, whether it's a predator-prey relationship, or a parasite-host interaction," said Charlat. "In the case of H. bolina, we're witnessing an evolutionary arms race between the parasite and the host. This strengthens the view that parasites can be major drivers in evolution."

Regardless of which route natural selection took, Gregory Hurst the co-author of the study appearing in today’s issue of the journal Science, thinks the end result is still a stunningly rapid evolutionary response to an environmental change.

"We usually think of natural selection as acting slowly, over hundreds or thousands of years," Hurst said. "But the example in this study happened in a blink of the eye, in terms of evolutionary time, and is a remarkable thing to get to observe."

In 2002, Hurst and his colleagues identified Wolbachia as the cause of the lopsided sex ratio. He holds a current post as a reader in ecology and evolution at University College London.

LINK
UC - Berkely news release

Tags : evolution, heredity, natural selection

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