Question

How do HOX genes affect evolution?

Answer 1

Hint: Evolutionary biology involves study of history of various life forms on earth. The study of evolution generally describes how the higher life forms of life have gradually arisen out of lower. It is a gradual orderly change from one condition to another.

Complete answer:
-HOX proteins are a group of homeo-domain containing factors that are involved in patterning animal body plans and these proteins are defined by the presence of a DNA binding region which is highly conserved in nature called homeodomain. This region of DNA is encoded by homeobox genes or HOX genes.
-In many animals like human beings, flies and worms these genes help layout their basic body forms. These genes are a large family of similar genes that can be divided into 11 different classes in animals.
These genes are inactivated or over activated due to mutations which may result in the development of body structures at wrong places.
-Small changes in such genes can be a major source of an evolutionary change in the organism. It is linked to the evolution of human body plans and morphology in case of mutations. It has been suggested that due to expansion and evolution of HOX genes there has been rapid diversification of the body plans of all Bilaterians. So the HOX genes are a great example of how developmental genes can be modified to evolution.

Note: The HOX genes have been duplicated over evolutionary history in vertebrates like humans and mice and now they exist as four similar gene clusters. These were first discovered in Drosophila melanogaster.