Reference "Classification and evolution of alpha-amylase genes in plants"

Reference ID

9274

Title

Classification and evolution of alpha-amylase genes in plants

Source

Proceedings of the National Academy of Sciences of the United States of America, 1992, vol. 89, pp. 7526-7530

Authors (3)

Huang-N	Stebbins-G-L
Rodriguez-R-L

Abstract

The DNA sequences for 17 plant genes for alpha-amylase (EC 3.2.1.1) were
analyzed to determine their phylogenetic relationship. A phylogeny for these
genes was obtained using two separate approaches, one based on molecular clock
assumptions and the other based on a comparison of sequence polymorphisms (i.e.,
small and localized insertions) in the alpha-amylase genes. These polymorphisms
are called "alpha-amylase signatures" because they are diagnostic of the gene
subfamily to which a particular alpha-amylase gene belongs. Results indicate
that the cereal alpha-amylase genes fall into two major classes: AmyA and AmyB.
The AmyA class is subdivided into the Amy1 and Amy2 subfamilies previously used
to classify alpha-amylase genes in barley and wheat. The AmyB class includes the
Amy3 subfamily to which most of the alpha-amylase genes of rice belong. Using
polymerase chain reaction and oligonucleotide primers that flank one of the two
signature regions, we show that the AmyA and AmyB gene classes are present in
approximately equal amounts in all grass species examined except barley. The
AmyB (Amy3 subfamily) genes in the latter case are comparatively
underrepresented. Additional evidence suggests that the AmyA genes appeared
recently and may be confined to the grass family.