Abstract Detail

Genetics Section

Mena-Alí, Jorge I. [1], Travers, Steve [1], Stephenson, Andrew G. [1].

S-allele diversity and sequence divergence in horsenettle (Solanum carolinense).

We used a modified protocol to obtain and sequence the cDNAs for the S-alleles present in the styles of 28 plants from two natural populations of horsenettle (Cumberland, MD and State College, PA). We found 16 S-alleles: 11 in the MD population and only 5 in the PA population. There were five new alleles—3 in the MD population and 2 in the PA population. The other 3 alleles in the PA population were also shared with the MD population. Unlike other studies looking at the diversity of S-alleles, the allele frequencies in each of our two populations departed significantly from equal. Eleven of the 30 S-alleles sampled from the MD population and 13 of the 26 S-alleles sampled from the PA population were identified as the S₈ allele (previously found in both the NC and TN populations). Such deviation from equal S-allele frequencies may reflect biological differences associated with specific S-alleles. We compared the similarity of individual sequences for different copies of the S₈ allele in order to determine the level of intra-allelic sequence variation and to identify regions with high substitution rates. We expect a higher level of sequence divergence in allelic copies from different populations relative to the observed variation in copies from within the same population. In addition, we assessed the functionality of the different copies of the S₈ allele by performing a series of controlled pollinations, using plants from the same and different populations. We expect that alleles from different populations will fail more often to reject pollen bearing the S₈ allele, due to the lower degree of sequence similarity. Finally, we will look for associations between the degree of sequence divergence, the location of the substitutions within the allele and the level of functionality of the S₈ allele.

1 - Pennsylvania State University, Department of Biology, 208 Mueller Lab, University Park, Pennsylvania, 16802-5301, USA

Keywords:
cDNA cloning
self-incompatibility
Solanaceae
Solanum carolinense
S-alleles.

Presentation Type: Paper
Session: 53-12
Location: Peruvian (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 4:00 PM
Abstract ID:512