Analysis Of Flower Genes Reveals The Fate Of An Ancient Gene Duplication

Aug 23, 2005

In a step that advances our ability to discern the ancient evolutionary relationships between different genes and their biological functions, researchers have provided insight into the present-day outcome of a single gene duplication that occurred over a hundred million years ago in an ancestor of modern plants.

The work is reported in Current Biology by a team led by Brendan Davies of the University of Leeds, England.

Gene duplication - a relatively uncommon event in which a single copy of a gene is transformed into two separate copies - is thought to play a key role in the evolution of new gene functions.

Duplications are important because they effectively allow at least one of the gene copies to evolve while the (likely important) function of the original gene can remain intact.

In this way, the duplication of pre-existing genetic information provides the raw material from which new gene functions can evolve, thereby contributing to the evolution of genetic complexity and the evolution of sophisticated life forms.

Very many such gene-duplication events have shaped the evolution of today's living species, but tracing the evolution of a specific single gene over millions of years of evolution - and over potentially several gene-duplication events - can pose a significant challenge.

One way in which this can be overcome is for researchers studying a particular modern-day gene to look at neighboring genes in different related species.

Genes derived from a common ancestral gene region will still share similarities in neighboring gene sequences, both in terms of gene identity and the order such sequences appear within the chromosome. This kind of preserved gene order is known as genome synteny.

In the new work, researchers have used synteny to clarify the evolution of genes essential for the development of floral reproductive organs, stamens and carpels.

The subjects of their work were two genes that appear to play identical functions in two different plant species: the AGAMOUS (AG) gene of the mustard plant Arabidopsis thaliana and the PLENA (PLE) gene of the snapdragon, Antirrhinum majus. Both genes are required for the development of flower reproductive structures, and when these genes are mutated, the plants form so-called double flowers, in which petals and sepals replace stamens and carpels.

AG and PLE are very closely related genes, and they clearly have nearly identical function, suggesting that they are derived from the same single gene inherited from a common ancestor.

However, analysis of synteny in the AG and PLE regions unambiguously showed that AG and PLE are not derived from the same ancestral gene, but that they instead represent two different products of a gene-duplication event that occurred around 125 million years ago in a common ancestor of Arabidopsis and Antirrhinum.

The other genes created in that ancient gene-duplication event became altered, in different ways, so that they now have new functions in Arabidopsis and Antirrhinum.

These findings provide one of the first demonstrations of how an essential developmental function can be randomly assigned to either product of a gene-duplication event. The work defines a new standard for the evidence required to establish the evolutionary relationships of genes from different species.

Explore further: New research shows sportswomen still second best to sportsmen... in the press

add to favorites email to friend print save as pdf

Related Stories

Evolution: The genetic connivances of digits and genitals

Nov 20, 2014

During the development of mammals, the growth and organization of digits are orchestrated by Hox genes, which are activated very early in precise regions of the embryo. These "architect genes" are themselves regulated by ...

Scientists map mouse genome's 'mission control centers'

Nov 19, 2014

When the mouse and human genomes were catalogued more than 10 years ago, an international team of researchers set out to understand and compare the "mission control centers" found throughout the large stretches ...

House fly sex may reveal one key to controlling them

Nov 18, 2014

The quest of University of Houston professor Richard Meisel to understand how and why males and females differ may one day lead to a more effective means of pest control - namely, the pesky house fly.

Recommended for you

Passengers boarding airplanes—we're doing it wrong

4 hours ago

'Tis the season for airplane travel. We may be looking forward to getting where we're going, but most aspects of the travel itself are merely endured. There's stressful security, the madding crowd and the ...

User comments : 0

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.