A joint research project conducted at UNIL and EPFL enabled the scientists to follow the evolution of communication in 100 groups of 20 robots over the course of 1000 generations. The robots were equipped with a camera that detected the environment, and also with wheels and a ring enabling them to emit luminous signals of different colors. Positioned in arenas, they had to locate a source of virtual food that was only visible when they came upon it. Their behavior was guided by a “neural network”, which was also controlled by genes that could evolve through mutation and selection in the course of successive generations.

An initial experiment showed that the robots rapidly acquire a communication system that enables them to transmit information about the location of the food to their peers. In fact, two really distinct communication systems evolved, according to the given populations. The simplest mechanism, using a single color to indicate the location of the food, proved more effective that the system using two colors – one pointing towards the food and the other towards the remaining part of the arena.

It also became evident that a population that has evolved towards a relatively effective type of communication doesn’t subsequently change it, as it would then be necessary to simultaneously modify the way the information is transmitted, and also the way of responding. In other words, a communication system, just like a language, cannot change rapidly through generations. In addition, this research underlines the importance of random factors in evolutionary processes. The experiment performed in twenty homogenous groups (with robots of the same type) actually shows that half of them choose the simpler – one color – strategy, whereas the other half opt for the two color system.
A new University of Florida study shows genomes of a recently formed plant species to be highly unstable, a phenomenon that may have far-reaching evolutionary consequences.

Published online this week in the Proceedings of the National Academy of Sciences, the study is the first to document chromosomal variation in natural populations of a recently formed plant species following whole genome doubling, or polyploidy. Because many agricultural crops are young polyploids, the data may be used to develop plants with higher fertility and yields. Polyploid crops include wheat, corn, coffee, apples, broccoli and some rice species.

“It could be occurring in other polyploids, but this sort of methodology just hasn’t been applied to many plant species,” said study co-author Pam Soltis, distinguished professor and curator of molecular systematics and evolutionary genetics at the Florida Museum of Natural History on the UF campus. “So it may be that lots of polyploids — including our crops — may not be perfect additive combinations of the two parents, but instead have more chromosomes from one parent or the other.”

Researchers analyzed about 70 Tragopogon miscellus plants, a species in the daisy family that originated in the northwestern U.S. about 80 years ago. The new species formed naturally when two plants introduced from Europe mated to produce a hybrid offspring, and hybridization was followed by polyploidy.

Using a technique called “chromosome painting” to observe the plants’ DNA, UF postdoctoral researcher and lead author Michael Chester discovered that while whole genome doubling initially results in a new species containing 12 chromosomes from each parent, numbers subsequently vary among many plants.

The paints are made by attaching different dyes to DNA of the two parent species. Once the dye is applied, there is a match between the DNA of the paint and of the chromosome. Under a microscope, the chromosomes appear in one color or the other (red vs. green) depending on the parent from which they originated. Sometimes chromosomes are a patchwork of both colors because DNA from the two parents has been swapped as a result of chromosomal rearrangements.

“One of the things that makes this so amazing is that where we expected to see 12 chromosomes from each parent (the polyploid has 24 chromosomes), it turns out there aren’t 12 and 12, there are 11 from one parent and 13 from the other, or 10 and 14,” Soltis said. “We’re hoping through some ongoing studies to be able to link these results with the occurrence of another interesting phenomenon — the loss of genes — and also see what effect these changes have on the way the plants grow and perform.”

The polyploid’s two parent species, Tragopogon dubius andTragopogon pratensis, were introduced to the U.S. in the 1920s. Because its flower only blooms for a few hours in the morning, Tragopogon miscellus is often referred to as “John-go-to-bed-at-noon,” and its common name is goatsbeard. It looks like a daisy except for being yellow in color.
A new University of Florida study shows genomes of a recently formed plant species to be highly unstable, a phenomenon that may have far-reaching evolutionary consequences.

Published online this week in the Proceedings of the National Academy of Sciences, the study is the first to document chromosomal variation in natural populations of a recently formed plant species following whole genome doubling, or polyploidy. Because many agricultural crops are young polyploids, the data may be used to develop plants with higher fertility and yields. Polyploid crops include wheat, corn, coffee, apples, broccoli and some rice species.

“It could be occurring in other polyploids, but this sort of methodology just hasn’t been applied to many plant species,” said study co-author Pam Soltis, distinguished professor and curator of molecular systematics and evolutionary genetics at the Florida Museum of Natural History on the UF campus. “So it may be that lots of polyploids — including our crops — may not be perfect additive combinations of the two parents, but instead have more chromosomes from one parent or the other.”

Researchers analyzed about 70 Tragopogon miscellus plants, a species in the daisy family that originated in the northwestern U.S. about 80 years ago. The new species formed naturally when two plants introduced from Europe mated to produce a hybrid offspring, and hybridization was followed by polyploidy.

Using a technique called “chromosome painting” to observe the plants’ DNA, UF postdoctoral researcher and lead author Michael Chester discovered that while whole genome doubling initially results in a new species containing 12 chromosomes from each parent, numbers subsequently vary among many plants.

The paints are made by attaching different dyes to DNA of the two parent species. Once the dye is applied, there is a match between the DNA of the paint and of the chromosome. Under a microscope, the chromosomes appear in one color or the other (red vs. green) depending on the parent from which they originated. Sometimes chromosomes are a patchwork of both colors because DNA from the two parents has been swapped as a result of chromosomal rearrangements.

“One of the things that makes this so amazing is that where we expected to see 12 chromosomes from each parent (the polyploid has 24 chromosomes), it turns out there aren’t 12 and 12, there are 11 from one parent and 13 from the other, or 10 and 14,” Soltis said. “We’re hoping through some ongoing studies to be able to link these results with the occurrence of another interesting phenomenon — the loss of genes — and also see what effect these changes have on the way the plants grow and perform.”

The polyploid’s two parent species, Tragopogon dubius andTragopogon pratensis, were introduced to the U.S. in the 1920s. Because its flower only blooms for a few hours in the morning, Tragopogon miscellus is often referred to as “John-go-to-bed-at-noon,” and its common name is goatsbeard. It looks like a daisy except for being yellow in color.

Published On: January 13, 2012

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.