Mutations: Unlocking Humanity's History

Author:  Natasha Hochlowski
Institution:  Princeton University
Date:  June 2009

This past month, scientists from Cornell University published a paper in the journal GENETICS that detailed a new tool for identifying groundbreaking events in the history of humanity's evolution. This tool also serves to hone in on the origins of mutations, or permanent changes, in genes, the working subunits of DNA. By determining the source of genetic mutations, scientists can come closer to understanding and treating the origins of numerous diseases.

According to Kirk E. Lohmueller, one of the researchers on this project, "We know that many diseases are caused by a combination of genetic and environmental factors. To find the genes that contribute to disease, it's very helpful to know the demographic history of the population being studied."

Previously, research had focused on each mutation individually, rather than comparing them to understood patterns. But Lohmueller and the rest of the research team used computer simulations to model an expected relationship among DNA segments containing single nucleotide polymorphisms (SNPs). An SNP is a tiny genetic mutation that only involves one nucleotide,the molecule that is the building block of DNA. Looking for patterns in the mutations can help the scientists to understand potentially harmful effects. As Lohmueller said, "Accurate estimates of population events help inform the search for mutations that might have been helpful and necessary for survival at the time, but no longer necessary and potentially harmful today."

Demographic studies have shown that, throughout history, humanity has undergone serious dips in population. Researchers are now beginning to understand that these drops were not random occurrences; although they may have been influenced by environmental factors, they frequently were caused by genetic mutations. By developing new methods to examine mutations, the research team was able to analyze minute differences in people's genes, helping them understand genetic mutations and determine the basis for times in history when humanity moved close to extinction. Their research has confirmed the belief that between 32,500 and 47,500 years ago, a bottleneck, or major decline, in European populations occurred. By understanding the source of such population declines, scientists can better predict the occurrence of such declines in the future.

With more research using these methods, it will become easier to understand why certain demographic groups are more likely to develop cancer, heart disease, diabetes, and other diseases. The more we understand our biological history and the importance of our individual genetics, the easier it will be to target and to develop effective treatments for genetic diseases. The overwhelming importance of the research has been highlighted by Mark Johnston, the Editor-in-Chief of GENETICS, who stated, "What makes this development so amazing is that it helps align these [historical or geological] records with an emerging biological record based on our DNA. This technique can be applied to any species, making it possible for us to learn and compare the biological histories of all living creatures."

Written By: Natasha Hochlowski

Edited by: News and Features Editor Jess Kloss and Professional Reviewer Ron Thomas

Published by Falishia Sloan