Divergence

About: Divergence is a research topic. Over the lifetime, 748 publications have been published within this topic receiving 10357 citations. The topic is also known as: div & ∇ ·.

The Relative Importance of Characters Affecting Genetic Divergence

Abstract: The method for the identification of the most potent character contributing to divergence used by several workers is faulty. They have mistakenly treated the uncorrelated transformed variables (Yi) as biological characters having one-to-one correspondence with the original characters (Xi). A more rational approach has been given in the present work. It is suggested that the vector derived from the canonical vector corresponding to the largest root of the “between” populations matrix of the uncorrelated transformed variables and the triangular matrix of the transformation involved be used to identify the character contributing the most to the overall divergence. Further confirmation of the results could be made by distributing the components of D2 values in the form of a two-way table, obtaining the column totals over all possible values of D2 and identifying the character with the column giving the largest total.

How much of the variation in adaptive divergence can be explained by gene flow? an evaluation using lake-stream stickleback pairs

Abstract: How much of the variation in adaptive divergence can be explained by gene flow? The answer to this question should objectively reveal whether gene flow generally places a substantial constraint on evolutionary diver- sification. We studied multiple independent lake-stream population pairs of threespine stickleback (Gasterosteus acu- leatus). For each pair, we quantified adaptive divergence based on morphological traits that have a genetic basis and are subject to divergent selection. We then estimated gene flow based on variation at five unlinked microsatellite loci. We found a consistent and significant pattern for morphological divergence to be positively correlated with genetic divergence and negatively correlated with gene flow. Statistical significance and the amount of variation explained varied within and among traits: 36.1-74.1% for body depth and 11.8-51.7% for gill raker number. Variation within each trait was the result of differences among methods for estimating genetic divergence and gene flow. Variation among traits likely reflects different strengths of divergent selection. We conclude that gene flow has a substantial effect on adaptive divergence in nature but that the magnitude of this effect varies among traits. An alternative explanation is that cause and effect are reversed: adaptive divergence is instead constraining gene flow. This effect seems relatively unimportant for our system because genetic divergence and gene flow were not correlated with ecologically relevant habitat features of lakes (surface area) or streams (width, depth, flow, canopy openness).

Rapid divergence in expression between duplicate genes inferred from microarray data.

Abstract: To investigate the utility of a region of wingless (wg) as a marker for molecular systematics, we compared wg sequences to mitochondrial COII sequences from twenty‐two nymphalid butterfly taxa and one outgroup. Compositional characteristics of the two gene regions are compared, and their contributions to a cladogram inferred from the combined data set are assessed. Primarily due to its uniform base composition, wg appears to become saturated more slowly than mtDNA, although the two genes appear to be evolving at quite similar rates. We suggest that wg will be a useful source of characters for phylogenetic studies of butterflies, and perhaps other insect taxa, with divergence times up to 60 million years ago.

Patterns of mitochondrial versus nuclear DNA sequences divergence among nymphalid butterflies : the utility of wingless as a source of characters for phylogenetic inference

Abstract: To investigate the utility of a region of wingless (wg) as a marker for molecular systematics, we compared wg sequences to mitochondrial COII sequences from twenty‐two nymphalid butterfly taxa and one outgroup. Compositional characteristics of the two gene regions are compared, and their contributions to a cladogram inferred from the combined data set are assessed. Primarily due to its uniform base composition, wg appears to become saturated more slowly than mtDNA, although the two genes appear to be evolving at quite similar rates. We suggest that wg will be a useful source of characters for phylogenetic studies of butterflies, and perhaps other insect taxa, with divergence times up to 60 million years ago.

Divergence in the spatial pattern of gene expression between human duplicate genes.

Abstract: Microarray gene expression data provide a wealth of information for elucidating the mode and tempo of molecular evolution. In the present study,we analyze the spatial expression pattern of human duplicate gene pairs by using oligonucleotide microarray data,and study the relationship between coding sequence divergence and expression divergence. First,we find a strong positive correlation between the proportion of duplicate gene pairs with divergent expression (as presence or absence of expression in a tissue) and both synonymous (K(S)) and nonsynonymous divergence (K(A)). The divergence of gene expression between human duplicate genes is rapid, probably faster than that between yeast duplicates in terms of generations. Second,we compute the correlation coefficient (R) between the expression levels of duplicate genes in different tissues and find a significant negative correlation between R and K(S). There is also a negative correlation between R and K(A), when K(A)