Corn genetics provides insight into the crop's historical spread across the Americas

December 15, 2017, Iowa State University
Corn genetics provides insight into the crop’s historical spread across the Americas
Credit: Research Square

Iowa State University scientists have taken a journey through the past by studying the genetic changes in corn brought about by domestication.

A study published in the peer-reviewed academic journal Genome Biology spotlights how demography, or changes in population size, shaped the genetics of . The study shows how genetic "bottlenecks" imposed by domestication of increased the prevalence of disadvantageous mutations present in the crop's genome today. Matthew Hufford, an assistant professor of ecology, evolution and organismal biology and senior corresponding author of the study, said understanding a crop's history allows scientists to predict with greater accuracy how domesticated species may respond to new environmental conditions.

The study's most significant findings are summarized in an animated video from the journal.

Corn was first domesticated roughly 10,000 years ago in central Mexico by selecting desirable traits of teosinte, a species of wild grass. Since then, domesticated corn has spread throughout the Americas. But, as early farmers selected plants for specific traits desirable for crop production, they created a bottleneck that limited the diversity of the available genepool.

"Natural selection usually works best when you've got larger populations," Hufford said. "Otherwise, drift and chance can increase the amount of deleterious alleles, and that's what we see here."

The deleterious alleles, or disadvantageous mutations in the , increased in frequency as a result of domestication and became even more common as corn spread further from its point of origin, according to the study. These mutations make it more difficult for the plants to survive and reproduce.

For instance, Hufford said corn varieties in the Andes region of South America, where geographic isolation places evolutionary pressure on crops, show elevated numbers of deleterious mutations.

Hufford and his research team, including the lead author and postdoctoral researcher Li Wang, sequenced the genomes of 31 corn varieties and four teosinte varieties for the study. Geographical comparisons, as well as analyses of various genetic markers, allowed the researchers to piece together an evolutionary timeline. The timeline shows a split between wild and domesticated species around 10,000 years ago.

But Hufford said gene flow, or crossing of domesticated species with teosinte, may have helped corn plants adjust to new environmental conditions as corn spread to high altitude regions across continents and may also have decreased the number of deleterious alleles in corn. This new understanding may help scientists predict how other domesticated , such as crops, may be able to adapt to new geographic and environmental surroundings, Hufford said.

Explore further: Scientists reach back through centuries of cultivation to track how corn adapted to different elevations, environments

More information:

Related Stories

How corn came to be

August 10, 2011

( -- Corn, as we know it, didn’t always exist. A Brigham Young University biology professor published a new study that identified the functions of a gene that may have helped transform a wild grass called ...

How do atmospheric shifts affect soil-dwelling microbes?

November 17, 2017

Rising levels of carbon dioxide, ozone and other gases can affect crop growth. Microorganisms inside crops, on their roots or within nearby soil also influence crops by contributing nutrients, curbing disease and combating ...

Maize genetics may show how crops adapt to climate change

September 15, 2016

With the onset of climate change and changes in irrigation, adapting food crops to grow in diverse environments could help feed the world. Now University of California, Davis, scientists are leading a major new project, funded ...

Recommended for you

The friendly extortioner takes it all

February 15, 2019

Cooperating with other people makes many things easier. However, competition is also a characteristic aspect of our society. In their struggle for contracts and positions, people have to be more successful than their competitors ...

A river of stars in the solar neighborhood

February 15, 2019

Astronomy & Astrophysics publishes the work of researchers from the University of Vienna, who have found a river of stars, a stellar stream in astronomical parlance, covering most of the southern sky. The stream is relatively ...

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.