Dennis Wall

General Interests:

(1) Gene evolution and its influences on operational levels of selection.
(2) Genetic structure, codon usage patterns and biases. Understanding the intricacies of genetic process and their modes of upward causation.
(3) Plant evolution: Diversification and radiation of plant life and concomitant ecological and phenotypic adaptations (especially with regards to island mosses).

Specific Research:

Trends and modes of diversification in the paleotropical endemic moss clade, Mitthyridium.

Specific objectives:

to reconstruct the history of Mitthyridium, a paleotropical endemic moss that has diversified across islands in the Pacific and Indian Oceans. This moss's genetic, developmental, morphological and ecological variation suggests its youth and status as a radiation. Further, the moss has a diversity in mode of reproduction (in a continuum from sexual to purely vegetative) that appears to vary within species rather than among them. As is well known, sex--gene flow--can have constraining, cohesive or creative forces on populations in nature. Thus, given its island distribution patterns (across many island chains in two oceans) and intraspecific variation in characters like mode of reproduction, Mitthyridium presents a unique system for testing alternative hypotheses of diversification. Mitthyridium presents a number of unique features that make it unlike other plant or animal systems. In short, Mitthyridium is ideal for questioning radiations and may help bridge the gap between population divergence and evolutionary diversification.