Molecular Evolution of Self Incompatibility in Plants

作为进化过程原料的遗传物质的多样性使生物体能够抵抗新的疾病或利用新的食物来源。存在许多机制来增加或减少遗传多样性的数量。近亲繁殖是一种关系密切的个体交配以产生后代的交配系统，它可以通过增加基因在血统上相同的可能性来减少自然种群的遗传变异。在植物中，当相同的基因是致死基因时，近亲繁殖会导致植株寿命缩短和作物产量降低。因此，一些植物进化出了一种自交不亲和机制，以防止自交受精和近交的有害影响。在许多植物物种中，自交不亲和功能是由单个基因编码的。自交不亲和基因不仅可以增加其编码位点的遗传变异，而且可以增加其附近基因的多样性。本研究的主要目的是研究马荨麻自交不亲和位点的核苷酸序列变异，以确定自交不亲和机制对这一独特遗传位点及其附近核苷酸位点的影响。

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.