It's In The Genes

The discovery of four tiny stands of genetic materials unlocks the secret of what sets up apart from apes.

21:02 10 May 2016

Scientists sequenced the entire human genome 13 years ago and were shocked to discover that ours and ape’s DNA varied by just 1.2per cent. A new study has now found that the variation may lie in another type of genetic material.

 

The scientists suggest that short fragments of RNA – a single stranded molecule made of similar chemicals to DNA – may have played a key role in shaping how our species evolved. Two of these were found in concentrations in brain tissue and may affect genes that play a role in the way our neurons work compared to other animals.

 

Dr Alicia Gallego, from the Institute of Evolutionary Biology in Barcelona, Spain, and her colleagues said: 'We suggest the studied molecular changes could have modified crucial microRNA functions shaping phenotypes that, ultimately, became human-specific.'

 

'Over the last years, attention has been focused on the role that regulatory elements may have played in shaping diversification among species and individuals that share extended genomic similarities.

'Certain specific changes in transcription factors and non-coding RNAs have been shown to be under positive selection and to contribute to determine phenotypic differences between species such as humans and chimpanzees.

 

'Among non-coding RNAs, microRNAs are key post-transcriptional gene regulators with a clear role in evolution that are implicated in almost every biological function and in many types of diseases such as cancer and neurological disorders.

 

'Expression and functional analyses of four microRNAs - miR-299-3p, miR-503-3p, miR-508-3p and miR-541-3p - revealed that lineage-specific nucleotide substitutions and changes in the length of these microRNAs alter their expression as well as the repertoires of target genes and regulatory networks.'