Thursday, 12 April 2012

WA saltbush species shows genetic diversity

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Atriplex cinereaPictured; Atriplex cinerea which, unlike Atriplex yeelirrie station, is found near salt lakes, sand dunes and coastal areas. Flickr: DracophyllaA NEW and highly restricted species of saltbush discovered in WA has been found to possess distinct population genetic structure.

The species has been given the temporary name of Atriplex yeelirrie station, after the pastoral property on which it was discovered, as further taxonomic work is required.

The study looked at the genetic diversity within this saltbush population and found that two known populations of the Atriplex species have very high genetic differences, even though they are only 30km apart.

Professor of Plant Conservation Biology at University of Adelaide and Director at the Australian Centre for Evolutionary Biology and Biodiversity, Professor Andrew Lowe led the research.

“We wouldn’t necessarily expect this finding for a plant species, because the levels of gene flow that naturally operate between individuals and between populations should be sufficient to minimise the amount of genetic structure that’s established in natural populations,” Prof Lowe says.

“What we are finding for this Atriplex species is that it has high genetic diversity and there’s quite a bit of difference between those populations.”

“As an indication, there’s about a 12 per cent difference in the genomes between those two populations, which would be more similar to the amount of structure that you would find across populations for a species that covers thousands of kilometers—so it’s very highly structured.”

Samples were collected from field sites on Yeelirrie Station and were analysed using the molecular marker method of nuclear microsatellites.

This method targets variable portions of the genome to establish how much genetic diversity is present within individuals, within populations, and how much variation is structured across the different populations.

“Part of this study really was to develop those markers in this plant species, and then apply them to understand the diversity and structure in those natural populations,” Prof Lowe says.

“It really is an interesting finding that there is high genetic structure within this species which has quite restricted distribution.

“That level of structuring we expect because there hasn’t been much gene flow between those populations that are quite close geographically.”

The findings indicate that these populations have been situated in a fairly similar distribution over a long period of time.

“It appears is that some WA species, rather than migrating, have a strategy to cope with climate change by adapting.”

“So it’s quite a ‘good-news story’ for future climate change adaptation,” he says.

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