Poster: Genome evolution

Abs # 839: Analysis of genetic variation in the Small Heat Shock Protein gene family in Arabidopsis thaliana and its close relatives.

Presenter:	Nguyen, Suzan
Authors	Nguyen, Suzan  (A)   Garcia, Janet  (A)   Starrett, James  (A)   Waters, Elizabeth R (A)
Affiliations:	(A): San Diego State University

The small heat shock protein (sHSP) family has 19 members in Arabidopsis thaliana. There are six Cytosolic I proteins, two Cytosolic II proteins, one Cytosolic III protein, one plastid, one ER, two mitochondrial localized proteins and six sHSP related proteins about which little is known. To better understand the genomic level forces acting on these genes and determine the levels and types of sequence variation for each of the sHSP genes within Arabidopsis thaliana we sequenced sHSP genes from 20 different A. thaliana accessions and from the related species Arabidopsis pumila, Arabis himalaica and Crucihmalaya lasiocarpa. The accessions chosen for study represent a large part of the natural range of A. thaliana from northern Russia, Finland and Sweden to populations from Morocco, Italy, Libya and Japan. The genes chosen for study included members from each of the six major families of sHSPs. In addition genes from each of the five A. thaliana chromosomes were studied. We obtained the sequence of the coding regions and the 5’ untranslated regions of each of the genes. Positions of Heat Shock Elements (HSEs) were determined by comparison with known sequences. Levels and types of variation (insertion, deletion or nucleotide substitution) for each of the genes were calculated for the coding region and the HSEs. We found that some genes possessed considerable variation in both the 5’ untranslated regions (including in the HSEs) and in the coding regions while other genes were nearly monomorphic. These results will be discussed in relation to the different functional constraints that may be acting of the individual sHSP classes.