PROVIDED BY
AND
This page has been archived and is no longer updated
Sexual reproduction, copy number variation and mutation are just a few of the different sources of genetic variation.
Copy number variations (CNVs) have been linked to dozens of human diseases, but can they also represent the genetic variation that was so essential to our evolution?
Is it possible to have "too many" mutations? What about "too few"? While mutations are necessary for evolution, they can damage existing adaptations as well.
DNA Replication and Causes of Mutation
Cells employ an arsenal of editing mechanisms to correct mistakes made during DNA replication. How do they work, and what happens when these systems fail?
Sexual Reproduction and the Evolution of Sex
Birds do it, and bees do it. Indeed, researchers estimate that over 99.9% of eukaryotes reproduce sexually. What, then, are the true costs and benefits of sex?
Variation at different loci can alter an organism's fitness.
How are humans contributing to negative selection? It's a part of evolution that can also drive some species to extinction; models of negative selection help us understand biodiversity.
Natural Selection: Uncovering Mechanisms of Evolutionary Adaptation to Infectious Disease
The evolutionary link between sickle-cell trait and malaria resistance showed that humans can and do adapt. But are the “bugs” that make us sick evolving as well?
Genetic variation between individuals and between species results in the great phenotypic diversity we observe in living (and extinct) organisms. What are some sources of this phenotypic variation? What does this variation teach us about the genetic v. environmental contribution to a phenotype?
Genetic variation in a population can result from a variety of things. What are the ways we can estimate trait heritability?
Phenotype Variability: Penetrance and Expressivity
Sometimes, identical genes will produce different expression patterns. Why? Geneticists are now examining the "penetrance" and "expressivity" of genotypes and their phenotypes.
Researchers are highly interested in determining the relative importance of both the genetic factors and the environmental factors that lead to variance in particular traits.
Adaptation and Phenotypic Variance
Why are the variable levels and patterns of genetic variation important? Knowledge about how traits vary can reveal the evolutionary dynamics that shape populations.
The Molecular Clock and Estimating Species Divergence
What is the molecular clock? Levels of molecular variation could be used, in principle, to estimate divergence times, serving as evolutionary "clocks" that "tick" at different rates.
