Well, according to a new study, blame the micro RNAs (miRNAs) linked to the X chromosome. The study, published in  BioEssays, investigated the observation that women live longer than males and are more able to fight off shock episodes of sepsis, infection or trauma. Thus, the researchers from Ghent University, Belgium, decided to take a look at the X chromosome and the miRNAs linked to it.

A new study, published in the Proceedings of the National Academy of Sciences, and performed by researchers at the university of Oxford, has shown that larger groups of birds are better at solving problems. The researchers suggest this effect may be explained through the higher chance that a ‘bright’ or ‘experienced’ bird is included in a larger group rather than in a smaller one.

This effect, also known as the ‘pool of competence’ is suggested to occur in human beings, but this study is the first one that hints it might also play a role in other animals.

In a protein coding sequence of DNA, three subsequent nucleotides form codons (see figure 1), which, in turn, form amino acids that will eventually give rise to a protein. Some of these codons, however, are synonymous, meaning that one amino acid can be encoded by several different codons. When an amino acid is preferentially encoded by one of several potential synonymous codons, it is called codon bias.

Figure 1: Example of a codon. (GCA codes for alanine, which is also encoded by the synonymous codons GCT, GCT and GCG.)

(Source: Georgia Southern University, Department of Biology.)

New research that includes representatives of 99% of mammalian families, has provided a ‘big picture’ for mammalian phylogeny. By assembling a large and robust DNA matrix, based on sequences of many different genes, a research team led by biologists from the University of California, Riverside and Texas A&M, has examined how different families are related to each other.