lecture 3.2 - Modern synthesis, early 20th century Flashcards
Who rediscovered Mendels work, and what new discovery did they also make?
Bateson, Punnett (and Saunders) all rediscovered Mendles laws.
They also discovered the idea of linkage - where DNA sequences that are close together on a chromosome are inherited together.
shows the idea that genes/characteristics are stuck on chromosomes.
Who made the first genetic map?
Alfred Henry Sturtevant- looked at linkage and which characteristics were tightly linked and showed that you could plot genes and predict how often genes would be inherited together and how often they would recombine apart.
He built up the genetic map until it matched the number of chromosomes in the cell.
Who discovered the first sex chromosome?
Nettie Stevens
Who did Alfred Henry and Nettie Stevens work with? And what did he/they do?
Thomas Hunt Morgan - crossed flies and counted offspring. Found the white eyed mutation in fruit flies (Drosophila)
He found that the factor for eye colour and sex were located on the same chromosome (linkage)
so found the chromosome theory of hereditary - genes are located on chromosomes like beads on string.
What did biometricians do?
They drew pedigrees - to try and see the characteristics of an offspring given their parents characteristics.
Experiment looking at intelligence/ genius - non-blended.
Who explained the biometricians results?
R.A.Fisher. Explained finding by considering non-blending genes.
