DISSERTATION RESEARCH: Estimating the Somatic Mutation Rate of the Tree Delonix regia

生物体中的突变可能以两种方式之一出现：作为减数分裂突变，出现在精子和卵子的产生过程中，或者作为体细胞突变，出现在正常细胞分裂和生长过程中发生的DNA复制过程中。 体细胞突变的典型速率基本上是未知的，但似乎比减数分裂突变的速率低许多倍。 在具有有限生长的短命生物中，总体突变率受到减数分裂突变率的强烈影响。 然而，在长寿的生物体中，如树木，细胞在生长过程中可能会分裂数百万次。因此，突变率可能更强烈地受到体细胞突变的影响。该项目将估计大型热带树木凤凰木的体细胞突变率。 在大的分支的基部和顶端产生的花将被检查在花粉适合度的几个措施的差异，和分离花的细胞分裂的数量将被估计。 这些估计值将用于确定每次细胞分裂的体细胞突变率和每个体细胞突变的平均效应。突变率的知识对生物学的许多领域都是至关重要的。 体细胞突变尤其可以对人类福利产生巨大影响（例如，通过引起癌症），这里测量的体细胞突变率可以被其他科学家用来确定其发生的一般可能性。

Mutations in organisms may arise one of two ways: as either a meiotic mutation, which appears during the production of sperm and eggs, or as a somatic mutation, which appears during the duplication of DNA that occurs during normal cell division and growth. The typical rate of somatic mutation is essentially unknown, but appears to be many times less than the rate of meiotic mutation. In short-lived organisms with limited growth, the overall mutation rate is strongly influenced by the rate of meiotic mutation. In long-lived organisms such as trees, however, cells may divide millions of times during growth. Thus, the rate of mutation may be more strongly influenced by somatic mutation. This project will estimate the rate of somatic mutation in the large tropical tree Delonix regia. Flowers produced at the base and apex of large branches will be examined for differences in several measures of pollen fitness, and the number of cell divisions separating flowers will be estimated. These estimates will be used to determine the rate of somatic mutation per cell division and the average effect of each somatic mutation. Knowledge of mutation rates is of fundamental importance to many areas of biology. Somatic mutation in particular can have dramatic impact on human welfare (e.g., by giving rise to cancers), and the rate of somatic mutation rate measured here may be used by other scientists seeking to determine the general likelihood of their occurrence.