PRF/J: Molecular Evolution in Strepsirhine Primates

这里的目的是生成和比较线粒体和核DNA序列，以探索链状灵长类动物（如狐猴和懒猴）序列进化的速度和模式。这项研究的主要目的是测试两个独立的假设：(a)与懒猴和其他灵长类动物相比，狐猴的分子进化速度是否较慢？(b)狐猴是否表现出较慢的过渡速度？如果可以证明狐猴相对于其他灵长类动物经历了分子减速，这将表明世代时间不是控制灵长类动物进化速度的主要变量。分子进化总速率的降低与过渡速率的降低相一致，这表明总速率可以被延缓或加速的机制。为统一的分类样本生成的大量mtDNA和核DNA序列将能够比较两个数据集的进化速率和系统发育。这种方法的一个主要研究优势是，分子进化现象将在一个健全的系统发育背景下进行探索。结果有望阐明我们对链霉素进化的理解，更具体地说，马达加斯加狐猴是生物多样性的例证。此外，这些发现将影响正在进行的关于分子钟真实性的辩论。目前争论的主要原因是缺乏共识，部分原因是许多研究缺乏系统发育基础。该研究的第三个理由是它对核与线粒体核苷酸序列的评估，这是一种不常采用的方法。估计mtDNA的大小和核速率差异可能会影响这些基因的系统发育效用。

The intent here is to generate and compare mitochondrial and nuclear DNA sequences in order to explore the tempo and mode of sequence evolution in strepsirhine primates (e.g., lemurs and lorises). The primary objective of this research is to test two discrete hypotheses: (a) do lemurs show a reduced rate of molecular evolution compared to lorises and other primates?, and (b) do lemurs exhibit a slower transition rate? If it can be demonstrated that lemurs have experienced a molecular slowdown relative to other primates, this would indicate that generation time isn't the principal variable responsible for controlling the rate of primate evolution. A reduced overall rate of molecular evolution coincident with a depressed transition rate would be suggestive of a mechanism whereby overall rates can be retarded or accelerated. The large number of mtDNA and nuclear DNA sequences to be generated for a uniform taxonomic sample will enable comparisons of rates of evolution and phylogenies for the two data sets. A prime research strength of this approach is that molecular evolutionary phenomena are to be explored within a robust phylogenetic context. %%% Results are expected to shed light on our understanding of strepsirhine evolution and more specifically Malagasy lemuriforms, which exemplify biological diversity. In addition findings will impact the on-going debate over the reality of a molecular clock. The lack of consensus that predominates the current controversy is partly due to the poor phylogenetic grounding of many studies. A third justification for the study is its assessment of nuclear versus mitochondrial nucleotide sequences, an approach not taken so often. Estimation of the magnitude of mtDNA and nuclear rate differentials may affect the phylogenetic utility of those genes.