Blotting techniques in molecular biology:

• Southern blot analyzes DNA fragments; Northern blot analyzes RNA molecules; Western blot detects specific proteins using antibodies.
• Eastern blotting is an extension of Western blotting designed to detect post-translational modifications (PTMs) of proteins, such as carbohydrate epitopes, glycosylation, phosphorylation, and lipidation, using probes like lectins, cholera toxin, or phosphospecific antibodies.
• Therefore, Eastern blot evaluates post-translational modifications in proteins.

Hemoglobin polypeptide composition:

• Normal adult hemoglobin (HbA) represents $\approx 97\%$ of adult hemoglobin and is a tetramer composed of two alpha ($\alpha$) and two beta ($\beta$) polypeptide chains ($\alpha_2\beta_2$).
• Fetal hemoglobin (HbF) consists of two $\alpha$ and two gamma ($\gamma$) chains ($\alpha_2\gamma_2$).
• Minor adult hemoglobin ($HbA_2$) consists of two $\alpha$ and two delta ($\delta$) chains ($\alpha_2\delta_2$).
• Hence, HbA is $\alpha_2\beta_2$.

Genotype frequency calculation in a population:

• Carrying two specific distinct alleles ($A_1$ and $A_2$) corresponds to being heterozygous for these two alleles ($A_1 A_2$).
• Under Hardy-Weinberg equilibrium, the expected frequency of a heterozygote with allele frequencies $p$ and $q$ is $2pq$.
• Given $p = 0.2$ and $q = 0.2$: $\text{Frequency} = 2pq = 2 \times 0.2 \times 0.2 = 0.08$.
• Therefore, the probability is $0.08$.