Organisms can become resistant to new diseases or utilize a new food source as a result of diversity in their genetic material which serves as raw material for the evolutionary process. Many mechanisms exist to increase or decrease the amounts of genetic diversity. Inbreeding, a mating system where closely related individuals mate to produce offspring, can reduce genetic variation in natural populations by increasing the probability that genes are identical by descent. In plants, inbreeding can lead to short-lived plants and reduced crop yields when the identical genes are lethal genes. As a result, some plants have evolved a self-incompatibility mechanism that prevents self-fertilization and the harmful effects of inbreeding. In many species of plants, the self-incompatibility function is encoded by a single gene. The self-incompatibility gene can not only increase genetic variation at the locus that encodes it but may also increase diversity of genes located nearby. The main objective of this research is to study variation of nucleotide sequences of the self-incompatibility locus of Solanum carolinense, the horse nettle, in order to determine the impact that the self-incompatibility mechanism has on this unique genetic locus and on nearby nucleotide sites.
