Friday, February 03, 2012

Humans, Apes, Addicts, and Microbes: Common Thread

The common thread that links life on Earth is the thin thread of DNA that coils, circles, and works its way through the generations, through the species, changing the face of the planet as it evolves.

Our brains are formed by our genes, working through the environment. Some genes control an entire platoon of other genes. The genes that determine how our brains grow and function are still evolving. If these "commander" genes evolve, remarkable changes can occur over a fairly short time span. The human species appears to be changing on a more rapid time scale than most scientists are willing to accept.
...human beings have suites of genes that probably cause their brains to be “plastic” and thus receptive to change far longer (to the age of about five) than is true for chimps or monkeys (whose brains are plastic for less than a year after birth). Moreover, Dr Khaitovich was able to work out how the expression of these modules of genes was co-ordinated, by looking at the switches, known as transcription factors, that turn them on and off.

Indeed, by comparing modern genomes with their discoveries about Neanderthals Dr Paabo’s group has found that the regulatory process for one of the modules came into existence after the modern human and Neanderthal lines separated from one another, about 300,000 years ago. _Economist
Of course, it does no good to have brains that are more plastic, if the caregivers of young children do not take advantage of that period of plasticity to give the children skills, competencies, wisdom, and knowledge that will serve them well throughout their lives.

Some people may be born at a tremendous disadvantage, genetically speaking. Addictive and criminal behaviour appear to be at least partially heritable. Societies deal with these problems in different ways. There is always room for improvement -- beginning with the acknowledgement of the genetic component.

Humans have turned a corner in understanding their own genetics. They can now re-program the genes of living humans, and are on the verge of re-programming the genes of embryos and zygotes. Artificial evolution, in other words.

Humans are also making progress toward understanding the complex genetics of their environments -- the microbial world in which they are immersed. We live in microbial soup, which is quite difficult to sort out with the old genetic tools that required culturing organisms before their genomes could be sequenced.

Now, scientists can extract individual genomes out of the common slurry, and sequence these mystery guests.
To extract individual genomes, Armbrust’s PhD student Vaughn Iverson exploited skills that had he gained as a computer scientist designing video compression technology at Intel in Portland, Oregon. He developed a computational method to break the stitched metagenome into chunks that could be separated into different types of organisms. He was then able to assemble the complete genome of Euryarchaeota, even though it was rare within the sample. He plans to release the software over the next six months.

It’s a different tack from that taken by early marine metagenomics efforts, which began in earnest with Craig Venter’s Global Ocean Sampling effort in 20032. “Our survey offered a broad-stroke picture of microbial diversity and the dominant players in the world’s oceans,” says Kenneth Nealson, director of the microbial and environmental genomics group at the J. Craig Venter Institute in San Diego, California. “This clever approach demonstrates that they can pull out the sequence of uncultured organisms — information we need to get a clue as to how microbes share limiting resources in the ocean.” _Nature
We finally understand that it is necessary to understand the full complement and range of genomics, genetics, and epigenetics in which we live -- and how we interact with this milieu in order to work out our lives.

Genetics and evolution have been underrated and ignored by most human intellectuals. But no one -- including these neglectful intellectuals -- is ignored by the genetic universe we inhabit. Not one living thing.

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