Researchers discover how corn breaks genetics laws

May 11, 2018 by Alan Flurry, University of Georgia
Credit: CC0 Public Domain

Modern genetics is based on the idea that genes are passed on to progeny in a predictable fashion, as first described by 19th-century Austrian botanist Gregor Mendel. He determined that genes exist in pairs, and each one of the two has an equal chance of being transmitted to the next generation.

However, in rare exceptions, chromosomes are able to cheat this process and are passed on at a higher frequency.

It may come as a surprise that many heirloom varieties of corn contain just such a cheater. Called Abnormal chromosome 10, it cheats in the female part of the flower during meiosis, where it is regularly transmitted about 75 percent of the time instead of the normal 50 percent.

Now a team of researchers at multiple universities led by UGA Distinguished Research Professor of Genetics Kelly Dawe has discovered that Ab10 encodes a cluster of that code for specialized . These motor proteins bind to and actively pull them to the reproductive egg cell. The molecular motors are only found on Ab10, and they enable the Ab10 chromosome to bypass Mendel's law and be transmitted to more than 50 percent of the offspring.

The paper, "A kinesin-14 motor activates neocentromeres to promote meiotic drive in maize," was published in the journal Cell.

These so-called meiotic drive systems are suspected to have evolved and gone extinct many times in the history of both plants and animals. As in sports and other conflicts, the presence of cheaters has favored the evolution of new biological rules that thwart the cheaters and ensure overall fairness. It is rare to visualize a cheater in action, and rarer still solve its molecular mechanism.

"The mystery had been known for many years before I began studying it, and we have been trying to solve the problem in our laboratory for over
20 years," Dawe said. "It was very satisfying to finally find the genes, and even more satisfying to learn that molecular motors are powering the process."

Explore further: Molecular motor mystery solved: Novel protein rounds out plant cells' machinery

Related Stories

New steps in the meiosis chromosome dance

January 23, 2017

Where would we be without meiosis and recombination? For a start, none of us sexually reproducing organisms would be here, because that's how sperm and eggs are made. And when meiosis doesn't work properly, it can lead to ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

EPA adviser is promoting harmful ideas, scientists say

March 22, 2019

The Trump administration's reliance on industry-funded environmental specialists is again coming under fire, this time by researchers who say that Louis Anthony "Tony" Cox Jr., who leads a key Environmental Protection Agency ...


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.