Ernst Mayr wrote in 1963 that the concept ‘founder effect’ in genetics refers to an event when a small number of individuals carrying a fraction of their population's genetic variation are the founders of a new society elsewhere. As a result, the new population may be distinctively different in their genes from the parent population. In extreme cases the founder effect may lead to speciation and subsequent evolution of new species. A population bottleneck - caused for example by a catastrophic event like an earthquake or a flood or genocide that kills entire sections of a population - can also cause a founder effect even though it isn't strictly a new population but a small group of survivors of the old. A population bottleneck would reduce genetic variation further. Due to various migrations throughout human history, founder effects are quite common.

Mayr’s definition applies to all living organisms. I recently read a fascinating paper on the phenomenon of founder-effect speciation among the common Myna bird introduced to Australia, New Zealand, Fiji, Hawaii and South Africa from India, where the authors concluded that ‘in the evolutionarily short period of 100-120 years, bottlenecks and genetic drift have promoted genetic shifts equal to those between different sub-species of birds.’  Here I want to focus on modern human beings and the effect of colonization events on a select number of founder-effect diseases of the blood: Factor V Leiden, Porphyria and Sickle cell Anemia. I will end my lecture with some remarks on areas of possible collaboration between the South African and Australian medical and science communities.

Read the rest of this lecture by Dr Wlmot James, MP at Monash University, Melbourne, Australia