Archive for the ‘ Genetics ’ Category

More evidence against a “metabolism first” origin of life

New research by Universitat Autònoma de Barcelona, published in the Proceedings of National Academy of Sciences, has revealed problems with origin of life hypotheses that are based on metabolic systems developing first, as opposed to an RNA or DNA system. 

The researchers found that compound genomes, or “composomes”, the basic unit of proto-life in metabolism-based hypotheses, are unable to undergo Darwinian evolution, putting serious doubt onto thoughts that they could foster the beginning of life on planet Earth.

However, this is just one study – more research needs to be done to confirm or deny these results.

Eight percent of the human genome is bornaviral in nature

Bornaviruses, a type of RNA virus that replicates inside the nucleus of host cells, has been found to be responsible for up to eight percent of the content of the human genome. Through endogenization, the virus’s DNA, retrotransposed from the RNA genome, has been integrated with our chromosomes over evolutionary time. Once the viral sequences are in the genome, they can be inherited through reproduction like any other part of the genome.

Due to the nature of bornavirus infections – they only infect neurons, the cells that comprise brain tissue – researchers have hypothesised that bornavirus genome integration could be the source of psychiatric disorders such as schizophrenia. A fascinating idea, but one that will have to be backed up with solid evidence in the future.

Maize genome sequenced at last

Finally, scientists have sequenced the genome of maize, one of the world’s main food crops.

According to the newly published data, the maize genome has 2.3 billion base pairs (as compared to the 3 billion base pairs of the human genome), of which 85% is repetitive sequences. Ooh, nice. I can’t wait for that genetic mystery to be solved…