Lecture 2: Selection in Action
by David M. Kingsley, Ph.D.
Play Lecture Two in Full
Introduction by HHMI Vice President Dr. Peter Bruns
Introductory interview with Dr. David Kingsley
Natural selection and artificial selection
Artificial selection created corn (maize)
Video: Corn and ancestral teosinte
Ancient breeders selected seed and stalk traits
Genetic archaeology: How corn was bred
Mendelian inheritance pattern: A one-gene trait
How many genes result in maize/teosinte differences?
Only 4 to 5 genes changed to make corn from teosinte
Single genes can radically change an organism
Video: Dogs and selective breeding
Breeding has generated many dog varieties
The genetic basis of different dog skeletons
A German shepherd - basset hound cross
Genetic control of muzzle shape in dogs
Summary of dog genetics
Q&A: How much does modern genetics guide breeders?
Q&A: Why different genes for upper/lower jaw formation?
Q&A: How did corn breeders know what genes to change?
Q&A: What problems arise from inbreeding dogs?
Can natural selection create variation as breeders do?
Video: The stickleback on Jeopardy!
Ancestral sticklebacks spawned in freshwater streams
Video: Environmental pressures led to stickleback evolution
Adaptive radiation from ancestral form
Adaptive changes in freshwater sticklebacks
Crosses between stickleback forms reveal underlying genes
Important varieties in wild stickleback populations
Genetic basis for reduction in stickleback armor plating
Genetic archaeology locates the plate-number gene
Modifier genes also influence plate number
Genetic engineering adds armor to a plateless stickleback
Genetic control of stickleback hindfins
Limb reduction has occurred in many vertebrates
Animation: 3-D CT scan of stickleback skeleton
Hindfin reduction controlled by major and modifier genes
Artificial and natural selection give rise to variety
Review of how quickly selection can act
Q&A: Would domesticated dogs go extinct in the wild?
Q&A: Are there inbreeding effects with F1 crosses?
Q&A: Has artificial selection helped improve other crops?
Q&A: What fish are used with the stickleback crosses?
Q&A: Are dogs still closely related to wolves?
Closing remarks from HHMI Vice President Dr. Peter Bruns