-DNA stands for deoxyribonucleic acid. It's the genetic code that determines all the characteristics of a living thing.
-It contains the genetic instructions for the development and function of living things. These instructions are needed for an organism to develop, survive and reproduce. To carry out these functions, DNA sequences must be converted into messages that can be used to produce proteins, which are the complex molecules that do most of the activities in our bodies.
In general, negative selection eliminates from the population very harmful changes to proteins that kill or stop reproduction. ... The authors also found a correlation between genes predicted to be under negative selection and genes implicated in certain hereditary diseases
