Friday, December 14, 2012

The Other Hobbit

The first installment of The Hobbit has hit theaters today, but scientists continue studying the real-life ancient "hobbit," homo floresiensis of Indonesia, to find out more about the individual.  Susan Hayes, an anthropologist from Australia, has used her background in forensic science to produce a facial approximation of the h.floresiensis specimen, who lived around 18,000 years ago, and was about three feet tall, 70 pounds, and female:

This reconstruction was created by making a 3D image of the skull, then constructing a face over this image.  The key was determining to use the features of modern humans, rather than monkey-like features, as artists had perviously done.  This decision seems reasonable, since the hobbit is more closely related to humans than chimpanzees, for example - modern humans provide the best model for facial reconstruction.   Some of the most notable features of this female are her small eyes and small forehead.  This work is exciting in that it quite literally puts a face on a fairly recent relative of ours, but should be taken with a grain of salt at this point; it has been released without first being published in a peer-reviewed journal, and it remains quite approximate in nature.

Romani people come from India

Scientists collaborating from many European universities have completed a genome-wide study to trace the history of the European Romani population, commonly referred to as "gypsies."  Previous computational modeling of the Indo-European language family suggested that the Romani people's language originated somewhere in India (though the methodology of the study in question remains questionable from a historical linguistic standpoint).  This genome study was able to corroborate an Indian origin, particularly a northwestern one, and to pinpoint their departure from India to about 1500 years ago.

Based on 800,000 SNPs from a sample of 152 Romani people, as well as pre-existing SNP data for Europeans, Indians, Central Asians, and inhabitants of the Middle East, the researchers were able to study the Romani migration path in detail.  They found that the Romani generally stayed together on their journey toward Europe, mating only moderately with the local populations and suffering from two population bottlenecks before beginning to disperse once they reached the Balkans.

Once the Romani dispersed throughout Europe, different pockets mixed with the local European populations to varying degrees.  The Welsh Romani have mixed to a great degree; the easter European Romani mostly kept to themselves until recently; and the Portugues, Spanish, and Lithuanian Romani seem to have mixed with the non-Romani Europeans in the past but then started isolating themselves again more recently. 

This analysis was a great first step in beginning to understand the history of a marginalized group and will hopefully help in giving the Romani a sense of identity as they continue to overcome their status as social outcasts.

When being short is adaptive

As a tall person, I've always been told that I had an advantage in life - indeed, height correlates with some metrics of success.  However, researchers at the University College London that there are actually cases where it is evolutionarily advantageous for individuals to be shorter.

The researchers examined 89 small populations from various environments across the world who employed various subsistence strategies, then performed statistical analyses to determine what factors proved predictive of height.  While there was some effect of environment and a very minor role of diet, the strongest correlates were measures of life expectancy.  The shorter the projected lifespan of a population, the shorter the people would physically be.  This makes intuitive evolutionary sense -- if you're likely to die young, you should stop devoting energy to development earlier on in life so that you can start devoting energy to producing offspring.  This shorter development window (which also correlates with earlier onset of menstruation) means that individuals have less  time to grow.   On the other hand, if you're going to live longer, the increased energy associated with being larger would ultimately permit you to later devote more energy to reproduction.

While these findings were for modern human populations, they actually are informative for further back in our evolutionary history; as we evolved from australopthecus ancestors into the homo genus, increased intelligence might have brought about increased lifespan, allowing the more recent ancestors of humans to grow taller than their more apelike ancestors.

14 new genes linked with arthritis

Rheumatoid arthritis is a chronic disorder that primarily affects our flexible joints. It causes inflammation in the joints, resulting in swelling, stiffness, pain and reduced joint function.  Women are 3 times more likely to develop this disorder than men are.

A recent study (reported Nov 26 2012) conducted by researchers from the University of Manchester has identified 14 genes in both genders that are associated with the disorder. These 14 join another 32 genes that have already been identified in a previous study. Out of those 14, some of them were X-chromosome genes. This newly- established association between the X chromosome and the disorder could possibly help explain the significantly higher incidence of it in women, who have 2 X chromosomes, than in men, who have only 1.

Presently, about 1/3 of arthritis patients do not respond well to the medicine available on the market.  The results of this study will greatly improve clinical treatment of arthritis. Out of the 14 genes newly identified, 3 are currently "targets for drugs" - as in that we presently have drugs that are able to target those specific genes. The remaining 43 genes can & should be studied in terms of pharmacology to further develop our clinical treatment ability. 

Epigenetics underlie intergenerational transmission of homosexuality?

From a purely evolutionary standpoint, homosexuality may be seen to be a puzzling trait. As it doesn't increase -and in fact, can decrease- a person's reproductive success means that, according to the rules of natural selection, it should not be so common a trait as it is today, all over the world. Researchers have been trying to identify a genetic basis for homosexuality, seeing as how they seem to "run in families".

A new study has suggested that looking at the epigenome will be more fruitful than studying the genome. According to the article, some epi-marks (i.e. temporary switches that regulate gene expression) "affect sexual partner preference". Usually, epi-marks are "erased" between generations and are not passed on from parent to offspring. However, they can "escape erasure", and the sexual orientation of the parent can end up influencing the orientation of their offspring.

See here for a very unscientific response to the study:

Viruses can work together

Newsflash: viruses still smarter than we are

New research done at two English universities found that viruses can easily and transiently develop the ability to adjust their behavior based on how many other viruses there currently are in their host. This means that viruses don't infect a host on its own; it can work in conjunction with other viruses to maximize its spread (and its damage on the host population).

Furthermore, researchers found that the virus would only cooperate with similar viruses, i.e. viruses it was related to. When it infected alone, it would clone itself and then work with the newly cloned viruses to. When this was the case, all clones worked together to kill the host as slowly as possible to enable maximum replication of the virus. But when other viruses, to which it was not related, were present in the cell, it deliberately worked against them to kill the host cell faster so it could dominate the other viruses.

The study looked at a relatively simple virus, and thus the astonishing speed at which it can adapt its behavior is especially discouraging. Humans have been on a never-ending quest to evade/better the viruses like influenza that infect us, but this news tells us that we have a long way to go. The evolutionary arms race rages on.


Cocktail Chatter: Matt Killian (Anthropologist Finds Evidence of Hominin Meat Eating 1.5 Million Years Ago: Eating Meat May Have 'Made Us Human’)

Anthropologist Finds Evidence of Hominin Meat Eating 1.5 Million Years Ago: Eating Meat May Have 'Made Us Human’
via Science Daily

Anthropologists recently discovered a skull fragment in Tanzania that reveals that our ancient ancestors were eating meat more than 1.5 million years ago. This provides a new point of view of human psychology and brain development in ancient times. Other evidence includes stone butcher like tool engravings on ungulate fossils. "Meat eating has always been considered one of the things that made us human, with the protein contributing to the growth of our brains,” said Charles Musiba, Ph.D.,  a professor at the University of Denver who helped make the discovery. "Our work shows that 1.5 million years ago we were not opportunistic meat eaters, we were actively hunting and eating meat,” he also said. A common thought among scientists is that we truly became humans when we began eating meat and becoming ‘carnivorous-omnivorous creatures.’ Before this, developing hominins were omnivores leaning more toward herbivores. The two-inch skull fragment was dug up in northern Tanzania, specifically Olduvai Gorge, at a site that is considered ‘the cradle of mankind,’ because it has been a constant ground where anthropologists have found many clues of evolution. The fragment was said to belong to a two year old child, and it showed signs of a disease associated with anemia, porotic hyperostosis. Scientists concluded that the child’s diet was insufficient in certain nutrients that are linked to meat eating. This lack of meat may also have altered the mother’s breast milk, which would also cause nutrient deficiencies. "The presence of anemia-induced porotic hyperostosis…indicates indirectly that by at least the early Pleistocene meat had become so essential to proper hominin functioning that its paucity or lack led to deleterious pathological conditions," the study said. "Because fossils of very young hominin children are so rare in the early Pleistocene fossil record of East Africa, the occurrence of porotic hyperostosis in one…suggests we have only scratched the surface in our understanding of nutrition and health in ancestral populations of the deep past.” Scientists believe that the lack of meat eating may not have been by choice, but due to a scarcity in animal foods. The child had been lacking in specific vitamins B12 and B9, which leads researchers to believe meat eating dwindled. This research also leads anthropologists more in depth to the coming about of homo sapiens. Musiba said that the transition from herbivores and scavengers to omnivores and carnivores gave the hominins the protein that is need to give them an “evolutionary boost.” "Meat eating is associated with brain development,” Musiba said. "The brain is a large organ and requires a lot of energy. We are beginning to think more about the relationship between brain expansion and a high protein diet.”

Cocktail Chatter - Matt Killian