He demonstrated that SCD and sickle cell trait were due to the presence of abnormal 8-globin polypeptides in red blood cells. He demonstrated that the electrophhoretic mobility of B-globin from patients with SCD was different from that of healthy individuals. He demonstrated that both parents of multiple patients with SCD had low levels of sickled red blood cells. He hypothesized that SCD was a recessive trait and that the parents of patients with SCD would be heterozygous carriers. He demonstrated that the difference between B-globin polypeptides in individuals who were healthy and those with SCD is an amino acid substitution. He performed a peptide fingerprint analysis on B-globin from individuals with 84 84 and 89 88, which identified the segment of B-globin that was changed by the BS mutation. James Neel Linus Pauling Vernon Ingram
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Answer:
The options
a. New combinations of genes yielding genotypes of greater fitness
b. Few heterozygotes because of underdominance
c. Frequency-dependent selection, leading to fluctuations in fitness
d. Heterozygotes with greater fitness, owing to overdominance
e. A random assortment of genotypes because of genetic drift
The CORRECT ANSWER IS b.
b. Few heterozygotes because of under dominance
Explanation:
In genetics, underdominance (at times called "negative overdominance") is the opposite of overdominance.
It is the selection against the heterozygote, that leads to disruptive selection and divergent genotypes. It occurs in cases of inferior and reduced fitness (As in our case study, it is the different chromosomal fusions and inversions)
of the heterozygotic genotype to the dominant or recessive homozygotic genotype. It is unstable as it causes fixation of either allele.
Another example is the African butterfly species Pseudacraea eurytus, which makes use of Batesian mimicry to avoid predation. This species carries two alleles that gives a coloration that is alike to a different local butterfly species that is harmful to its predator. The butterflies who are heterozygous for this trait are observed to be intermediate in coloration and thus encounter an higher risk of predation and a decrease in the total fitness.
A mitochondria converts glucose to energy
<span>One of the advantages of genetic engineering is the ability to add vitamins and minerals supplements to food. The correct option is D. The other options given are disadvantages of genetic engineering. Apart from the advantages given here, genetic engineering has other merits, such as production of better agricultural products, increasing shelf life of products, elimination of diseases, etc.</span>
