ISU researchers have discovered a genetic pattern in cotton that may lead to improvements in cotton fibers.

A team lead by Jonathan Wendel, professor of botany, studied cotton, a polyploid, and its gene expression. Polyploids have double the number of chromosomes than a diploid. An example of a diploid is a human, where one set of genes is taken from the male and one is taken from the female. Polyploids take two sets of chromosomes from the mother and father, so all of their genes are doubled.

“The question is what happens to all of these genes, do they all stay active?” Wendel said.

Wendel and his team studied a set of 40 of the doubled genes in cotton. They discovered some of these genes are turned off and not exhibited, a phenomenon known as gene silencing.

The gene silencing was also organ-specific, said Keith Adams, a post-doctoral research fellow who worked on Wendel’s team. This means one copy of a gene could be silenced in one part of the cotton plant, and the other copy is silenced in another part of the plant, Adams said.

“[This] means that gene doubling immediately creates an incredible amount of diversity,” Wendel said.

Adams said Wendel’s team is investigating the cause of gene silencing in polyploids.

Polyploid gene silencing might be caused by methylation, Adams said. There are four genetic bases and there is a methyl group attached to each of these bases. If there are more methyl groups than normal, it causes methylation, which could cause the gene not to be expressed, Adams said.

There are many implications to this research, both immediate and long-term, Adams said.

“The implications are profound,” Wendel said.

The immediate application of this knowledge could mean the improvement of cotton fibers and making them longer and stronger, Adams said. It could also lead to a better understanding of gene expression, he said.

“It will teach us more about how life works, the basic biology of plants and the evolutionary process,” Wendel said.

Adams said corn, soybeans and many other plants are also polyploids. “What we learn [about polyploids] might be applicable for corn and soybeans,” he said.