Children of the wilderness

A young girl disappears in the forest while playing with a cousin. The cousin is found several days later, but no one can find the girl. Some time later, stories emerge from the forest about a girl seen walking alongside a tiger, about a wild woman walking around with long hair and nails, but she is never found and the search is eventually abandoned. Thirty-eight years later, she is finally rediscovered at the age of 42, after having wandered through the forests on the borders of three different countries. 

This sounds like a chapter from a magical realist novel, or some fairy-tale fable, but it is the true story of Ng Chhaidy from the district of Mizoram in India, close to the border with Myanmar. Chhaidy’s story is astonishing for the length of time that she has been missing, long enough for her to lose the ability to use language, even though she was fluent in her native Mara when she disappeared as a four-year-old. It seems remarkable to those of us living in the developed and urbanized world, far removed from close contact with forest and wilderness, that such a thing could happen in modern times. 

Do chimps have culture?

It's hard being human, or at least, to define what exactly makes us human. It used to be tool-making, but our close cousins the chimpanzees have been found to use tools, such as sticks to gather insects for food. Could culture, the inheritance of behaviors by learning, be the next "exclusively human" trait to fall?

Evolutionary anthropologists are studying chimpanzee communities throughout the West coast of Africa to determine if different groups indeed have different cultures and traditions. There is geographical variation in what specific behaviors chimps exhibit, but this alone does not confirm that there are different traditions:

Deciphering culture in the wild is difficult because researchers must ensure that behavioural differences between groups do not have other causes, such as variation in genetics or environmental conditions. "Why is it all chimps don't do everything? One solution is that there are hidden ecological differences between populations," says primatologist Richard Wrangham at Harvard University in Cambridge, Massachusetts. A behaviour could be linked to any number of variables such as amount of rainfall, the types of tree available, or the kinds of predator in the area, he says.

Read more at Nature News.

Human DNA contaminates genome databases

Scientists rely extensively on public databases of genomic sequences, such as GenBank, based in the USA, and the European EMBL. They might use this for detailed and exacting statistical studies of molecular evolution, or for doing a quick search to check whether a sequence they've just amplified is indeed what it is. Most biology students today have done a BLAST search at some point, underscoring the ubiquity and usefulness of these bioinformatics tools.

One big problem that haunts these sequence databases, however, is contamination and mis-annotation. Sequences are not always what they say they are, and scientists who don't carefully check the provenance of their data, or who trust that "because it's in GenBank it should be ok" may find their painstaking analysis to be in vain if they had used the wrong data to start with. While this problem is widely acknowledged, it comes as a surprise, perhaps to hear that nearly 20% of non-primate genomes in public databases have some degree of contamination from human sequences, probably DNA shed from the skin of the very scientists and technicians who prepared the material for sequencing.

Why non-primate genomes in particular? The research team from the University of Connecticut decided to use a particular short (less than 300 bases) sequence in the human genome, called AluY, which is repeated in great numbers and is highly conserved among humans and other primates. Alu elements are retrotransposons and an example of SINEs (short interspersed elements) that make up much of the genome. The AluY subfamily is derived from an insertion event that happened in the common ancestor of primates, and its specificity to primates is a marker of our common ancestry.

This is a creative use of past evolutionary events for tackling what is effectively an applied, technical question. It really helps to know some history!

Interspecies Monkey Play

From the NY Times's "Scientist at Work" blog: primatologist Anthony Di Fiore from NYU writes about watching a juvenile spider monkey play with juvenile woolly monkeys in Ecuador, a "a rare, long bout of interspecies play". Sadly the video associated with the article doesn't seem to show the playing monkeys....