Dominance

First, be careful when you do a google search on 'dominance'. I'm so naive sometimes.....

Anyhow, an interesting question came up today - what IS dominance? What causes one allele to be 'dominant' to another?

In certain cases it is pretty simple. The production of 'something' tends to be dominant to the production of 'nothing'. So 'wild type' alleles tend to be dominant to mutants that code for nothing. If the allele is coding for the production of an enzyme and a single copy of the allele produces more than enough then the heterozygote and the homozygote will have similar phenotypes - complete dominance. However if the homozygote produces just enough then the half expression of the heterozygote may result in a different phenotype. The pink flowers would be a good example here. The pink comes about by the production of only half as much red pigment.

After this it gets a bit more complicated and was, in fact, the subject of a fairly intense debate in the last century between two giants of the population genetics world: RA Fisher and Sewall Wright. If you are interested in this topic then here are a couple of entries into the literature: a blog post entitled ' Whatever happened to the Fisher-Wright controversy?' and an article in the Journal of Theoretical Biology on 'The Heat-shock Response and the Molecular Basis of Genetic Dominance'.

This time last year: Canterbury Tales

Beatrix versus the Botanists

When I was a sophomore at college in England I spent a summer working at the Freshwater Biological Association in the English Lake District. The cottage I stayed in was in a tiny village called Far Sawrey. Just down the road is the village of Near Sawrey which contains a small 17th century farm house where Beatrix Potter spent most of her later years, and where she wrote and set her many Peter Rabbit books.

Having mentioned it in class I thought I'd see if I could find out whether Beatrix Potter was happy in her later life or whether she resented being excluded from the male dominated scientific community. Thanks to the wonders of the internet I found a highly relevant book and, even better, the relevant chapter is available online as a sample chapter.

Chapter 1 of Liaisons of Life, Beatrix versus the Botanists, by Tom Wakeford describes Beatrix Potter's encounters with the scientific establishment. Fascinating reading and a picture of science at the turn of the century. Beatrix Potter was facing an uphill battle, not just as a woman in science but also in proposing lichens as a symbiotic and mutualistic association. James Crombie, a prominent English naturalist said:

"A useful and invigorating parasitism —who ever before heard of such a thing?"

and he described the relationship as:

"an unnatural union between a captive algal damsel and a tyrant fungal master."

After her aborted scientific career and her successful career as a children's author Beatrix Potter went on to a third, and equally successful career as a sheep breeder and conservationist in the English Lake District.