Number of live births
Number of infant deaths
Proportion of live births
that died during infancy
3. Recent scientific studies have documented variation in the alleles of Tibetan women. The alleles being
studied are indicated as A and B below and represent alternative versions of a trait that affects oxygen
content in the blood of the women. High oxygen content is important for survival at high altitudes.
Describe two pieces of evidence from the table below that support the claim that allele B is affected by
selection pressure.
Proportion of live births
that died before 15 years
of age
Average for
Mothers with "AA"
genotype (not as
well adapted)
4.45
3
1.69 (lot more b/c
not adapted to the
mountains)
40%
43%
Average for
Mothers with "AB"
genotype
4.76
0.62 (average)
10%
5
11%
4.62
I
Average for
Mothers with "BB"
genotype (survive
better)
J
6%
0.32 (less because
more adapted to the
mountains)
8%
8
1
11
L