PHYLOGENETIC UTILITY AND MOLECULAR EVOLUTION OF THE NUCLEAR ALCOHOL DEHYDROGENASE GENE IN PYRUS

A total of 25 accessions from 18 Pyrus species and an outgroup accession from Malus (M. sieboldii) were used to investigate the phylogenetic utility of Adh and its molecular evolution in Pyrus. The Adh gene in Pyrus consists of six different-sized introns and in this study a 650 bp region, containing the first two introns, was used for sequence analysis.
Four major Adh loci with particular length variation in the first intron were identified, and sequences of each locus were monophyletic in the dendrogram.
Divergent copies, representing one locus, could be found in most individuals.
Some of these polymorphic orthologs do not appear monophyletic possibly due to ancient hybridisation as well as lineage sorting.
Sequence divergence among different Adh loci ranged from 8% to 10%, while polymorphism within the Adh loci was quite low (<2%) and failed to reconstruct a robust phylogeny.
However, the clades received higher bootstrap value as compared to ITS, showing that introns of low copy number nuclear genes (LCNG) have great potential to improve phylogenetic reconstruction at the low taxonomic level.

International Symposium on Molecular Markers in Horticulture

Xiaoyan Zheng, Jing Liu, Yuanwen Teng

pear, Adh, molecular evolution, phylogenetic utility, hybridization, lineage sorting

https://doi.org/10.17660/ActaHortic.2010.859.31