Question

A typical prokaryotic cell has about 3,000 genes in its DNA, while a human cell has about 20,500 genes. About 1,000 of these genes are present in both types of cells. Explain how such different organisms could have this same subset of genes ?

Answer 1

The subset of genes shared by humans and prokaryotes originates from a common ancestor and has been retained over billions of years of evolution.

Step-by-step explanation:

This is was the right answer on my teachers test.

Answer 2

same DNA bases and HGT

Step-by-step explanation:

Even though we are different species, so much as different kingdoms, the DNA is always going to be the molecule that contains our genetic information and constitute our genes. This molecule is made up by the same structure: a sugar, a phosphate and a base like adenine, guanine, cytosine, thymine. Regardless if its a human, bacteria, fungi or a plant cell we all share this in common.

It is well known that we acquire our whole set of genes from our ancestors but some studies have shown that we also acquire genes from other organisms and its called horizontal gene transfer (HGT). HGT involves the movement of genetic material between different species. Since we've been sharing the world with a lot of prokaryotic organisms we might have experienced the HGT at some point of the evolution, and since our genetic material is made up of the same molecules, we can have the same subsets of genes working in both organisms.