Simple genetic mechanism may be behind the origin of species

Jan 30, 2009

(PhysOrg.com) -- Some of the secrets behind the emergence of new species have been uncovered in a genetic study, conducted in collaboration with bioscientists at The University of Nottingham.

Almost all plant species are known to have cross-breeds that sometimes produce infertile offspring. Now for the first time the team, led by the French National Institute for Agricultural Research, INRA-Versailles, has identified a simple genetic mechanism that may explain why this happens. The results have been published in the journal Science.

Professor Malcolm Bennett, Biology Director for the Centre for Plant Integrative Biology and Head of Division of Plant and Crop Sciences at The University of Nottingham said: “As plants evolve, their genes may get copied, moved around the genome, and inactivated. This will reduce the possibilities for fertile cross-breeds and, over time, may result in the emergence of distinct species. We're delighted that this study demonstrates this process in action.”

The study explains why the offspring of some cross-breeds are not viable and indicates a potential mechanism for the formation of sub-species in supposedly identical populations.

The researchers, specialists in the genetics of the model plant Arabidopsis thaliana, first noted that
offspring of the cross between two of the plant's natural strains, Columbia (Col) and Cape Verde Island (Cvi), did not fully obey Mendel's Laws of Inheritance. Researchers found that in specific genetic combinations of two parent genomes, some did not produce offspring at all.

Further investigation showed that a gene called HPA is carried by chromosome 1 in the Cvi strain, but in the Col strain a second copy is also found on chromosome 5. As the Col strain evolved, the copy of HPA on chromosome 1 became inactive. As a result, the two strains of Arabidopsis now have their functional HPA genes on different chromosomes. The HPA gene is responsible for the production of histidine, an essential amino acid that is necessary for reproduction to take place.

Embryos that inherit one inactive HPA gene from chromosome 1 of a Cvi parent and another from chromosome 5 of a Col parent cannot produce histidine and fail to develop.

If the gene isn't present the two different strains become incompatible, making it impossible for parent plants to produce offspring. Researchers were able to confirm this after observing that plants watered with a histidine solution were able to produce embryos that developed normally.

Provided by University of Nottingham

Explore further: Plants with dormant seeds give rise to more species

add to favorites email to friend print save as pdf

Related Stories

The reptile database

Jan 09, 2014

Experts predict that 2014 will be a big year for reptiles. Reptiles, which include snakes, lizards, turtles, crocodiles, tuataras and amphisbaenians, are projected to become the most diverse vertebrate group ...

Recommended for you

Plants with dormant seeds give rise to more species

1 hour ago

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers successfully clone adult human stem cells

5 hours ago

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

rab96
1 / 5 (1) Jan 31, 2009
This study only shows the mechanism of cross-breeds sometimes producing infertile offspring, so the only "secrets behind the emergence of new species" it reveals is why speciation does NOT work.

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...