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.
