Genetic Diversity and Distance from Africa It is hypothesized that humans originated in East Africa, and migrated from there. We compute a measure of genetic diversity for different populations, and the geographic distance of each population from East Africa (Addis Ababa, Ethiopia), as one would travel over the surface of the earth by land (migration long ago is thought to have happened by land). The relationship between these two variables is shown in Figure 2.57 and the data are given in GeneticDiversity.

(a) Describe the relationship between genetic diversity and distance from East Africa. Does there appear to be an association? If so, it is positive or negative? Strong or weak? Linear or nonlinear?

(b) Which of the following values gives the correlation between these two variables: $r=-1.22, r=$ $-0.83, r=-0.14, r=0.14, r=0.83$, or $r=1.22$ ?

(c) On which continent is the population with the lowest genetic diversity? On which continent is the population that is farthest from East Africa (by land)?

(d) Populations with greater genetic diversity are thought to be better able to adapt to changing environments, because more genetic diversity provides more opportunities for natural selection. Based only on this information and Figure 2.57, do populations closer or farther from East Africa appear to be better suited to adapt to change?

Figure 2.57 Genetic diversity of populations by distance from East Africa

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0.70 0.75 0.60 Genetic Diversity 0.65 AFRICA MIDDLE EAST EUROPE CENTRAL_SOUTH_ASIA EAST ASIA OCEANIA AMERICA 5000 10000 15000 Distance from East Africa (km) 20000 25000