Question

what is the gamete combination for this parental genotype? ttdd
options:
td, td, tt, td
t, t, d, d
td, td, td, td
tt, dd

Explanation:

Step1: Recall the principle of gamete formation

According to Mendel's law of independent assortment, for a genotype with two pairs of heterozygous genes (like \(TtDd\)), each pair of alleles segregates independently during gamete formation.

Step2: Determine the possible combinations

For the \(T - t\) pair, the possible alleles in gametes are \(T\) and \(t\). For the \(D - d\) pair, the possible alleles in gametes are \(D\) and \(d\).
Combining these independently:

• When \(T\) combines with \(D\), we get \(TD\).
• When \(T\) combines with \(d\), we get \(Td\).
• When \(t\) combines with \(D\), we get \(tD\).
• When \(t\) combines with \(d\), we get \(td\).

Answer:

TD, Td, tD, td