Plant Evolution in Action

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Plant evolution in action described in ScienceNOW 27 January 2009 and Science vol. 323, p623, 30 January 2009. Biologists at French National Institute for Agricultural Research, Paris are researching what keeps different species from breeding together and how new species are formed. Olivier Loudet and colleagues cross bred different varieties of thale cress, Arabidopsis thaliana, a small weedy plant whose complete genome has been sequenced. The plant grows in many places all over the world and there are many genetic variations.

Loudet’s team examined genes for histidine, an amino acid, in two varieties: one from Poland and one from the Cape Verde Islands. There are two genes for this, one on Chromosome 1 and another on Chromosome 5. In the island thale the gene on Chromosome 1 is not expressed at all, and in the Polish thale one of the two copies of the gene on chromosome 5 is partially deleted. When these two varieties were cross bred 11 percent of the embryo plants died. Other plants had smaller roots, which the scientists put down to a lack of histidine. Crosses of other varieties resulted in up to 25 percent non-viable offspring. Loudet claims his results mean that evolution of a single gene can rapidly lead to differences within a species. Leonie Moyle, an evolutionary geneticist of Indiana University, Bloomington, says the results are exciting because this is the first clear example of genetically incompatible lineages within the same species.

Editorial Comment: If these plant genes continue to lose pieces, or to not be turned on, eventually these two groups of plants would not be able to breed at all, and they could rightly be classified a separate species. However, this is “origin of species” by degeneration – devolution not evolution. The plants are still the same kind, and the splitting into two populations is the result of a downwards trend or loss, and not an evolution of new information, sideways or upwards. This degenerative process has probably occurred many times since the original Biblical kinds were created, and many species that appear similar, but don’t breed, could be the result of these types of genetic changes. As we have often said: change is real, but no observed change include any known evolution. (Ref. botany, reproduction, speciation)

Evidence News, 11 March 2009

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