When you hear the word natural selection, you may think of change, but new research suggests that this mechanism can also maintain similarities between populations.
Biologists have a fairly solid understanding of the basic processes of evolution. Genetic diversity in a population is the result of mutations, some of which produce traits that help individuals grow better in their current environment. These traits are likely to be inherited, while less useful traits tend not to be reflected in future generations. This is natural selection.
Evolutionary biologists most often study variation within and between populations and species, but there is more to life than what makes us all different.
“We always talk about the vast diversity of life, and we should. It’s incredible.” To tell Jeff Connor, an evolutionary biologist at Michigan State University, is the lead author of the new study.
“Natural selection has given us much of that diversity, perhaps most of it. But natural selection can also cause similarity.”
Connor and colleagues in the United States and China have developed wild radish (Raphanus raphanistrum). Once all pollen-producing organs were the same length, but now there are two short and four long stamens.
Unexpectedly, Previous research Although the reasons are unknown, it has been suggested that selection maintains this length difference, known as “anther separation.”
For a trait to evolve, additive genetic variation is required, with multiple genes contributing to the trait. In so-called constraints, this lack of dispersion tends to hinder evolution, even when evolution is favored.
Constraints are based on the idea that as species change over time, they somehow lose genetic flexibility, allowing certain traits to become stable across generations.
If natural selection is considered the driving force of change, then constraints are the brakes.
“What we do is flip that script a little bit,” Connor said. To tell. “We are suggesting that selection can also slow things down and create similarities as well as differences.”
The research team wanted to see if constraints in previous studies might have prevented anther separation from progressing. They artificially selected and bred wild radish to restore its appearance to a more primitive state with smaller gaps between stamens.
“If a trait responds to artificial selection, it clearly has the potential to evolve,” the authors write. explain in their paper.
“But if the trait is not responsive, then there is a constraint due to lack of genetic variation.”
The study included six generations and 3,437 wild radish plants were grown and measured. Through artificial selection, the researchers were able to reduce differences in stamen length by more than 30%.
This change is indicative of today’s radish and perhaps its appearance. relativesare unlikely to be constrained because they still have the genetic variation needed to evolve.
Instead, natural selection appears to maintain differences in stamen length.
“This family of plants has maintained this trait of four lengths and two shorts for more than 50 million years, and we can eliminate one-third of that difference in five generations, or five years. ” Connor said. To tell. “If things continue like this, I think we’ll go back to having six stamens of the same length.”
Scientists designed an experiment to investigate whether differences in stamen length confer any benefits to humans. R. Raffanistra It’s about how pollinators interact with plants.
“Natural selection is very important.” To tell Connor. “We’re learning that we can do a lot of things that people used to think we couldn’t do by choice.”
This research new botanist.