Describe the hypothesis that James Neel proposed to describe the inheritance pattern of SCD. What experimental methods did he use to prove his hypothesis?
What will be an ideal response?
In 1949, James Neel identified the inheritance pattern of SCD in a study that examined
42 parents of children with SCD. None of these parents had SCD. Neel was testing the genetic hypothesis that SCD is produced by a recessive allele and that the parents of children with SCD
are heterozygous carriers. He reasoned that if his hypothesis were correct, all the parents of SCD patients would show evidence of a low level of sickle-shaped red blood cells. In Neel's tests, the blood of all 42 parents of SCD patients displayed a small number of sickle-shaped red blood cells, confirming the hypothesis that the inheritance of SCD is explained by the presence of two alleles
in heterozygous carrier parents. The validation of Neel's hypothesis confirms that in SCD families, two alleles, βA and βS, can occur at the β-globin gene, and that there are three genotypes, βAβA (homozygous wild type), βAβS (heterozygous carrier), and βSβS (sickle cell disease). The hypothesis predicts that when two heterozygous carriers produce a child, the likelihood of the child having SCD is 1 in 4.
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Meerkats are small desert mammals that live in groups of 20–50 animals. You observe a female meerkat standing upright on a stump, looking around. Eight of her young nieces and nephews are foraging for food around her
You hypothesize that this is an example of kin selection. Which of the following supports your hypothesis? A. All adults in the group, including those that are not related to the young meerkats, are standing upright and looking around. B. The female meerkat in the question takes food from the foraging nieces and nephews when they find it. C. The female meerkat in the question spends her energy in all activities that involve caring for the young meerkats. D. Other aunts and uncles of the young meerkats are foraging, and do not spend any time standing up and looking around. E. All adults in the group, including those who are not related to the young meerkats, spend energy in all the activities that involve caring for the young meerkats.
Based on the structural similarity of vertebrate limbs, we can conclude that these structures are examples of ____
a. biogeography b. mutations in master genes c. analogous structures d. morphological convergence e. morphological divergence
The production of large quantities of a particular DNA sequence is known as gene ________.
Fill in the blank(s) with the appropriate word(s).
A woman with type A blood and a man with type B blood have a baby with type O blood. What are the genotypes of the woman and the man?
A) IAi and IBi B) IAIA and IBi C) IAi and IBIB D) IAIA and IBIB