Get the answers you need at Westonci.ca, where our expert community is dedicated to providing you with accurate information. Explore our Q&A platform to find reliable answers from a wide range of experts in different fields. Discover in-depth answers to your questions from a wide network of professionals on our user-friendly Q&A platform.

The offspring of a particular cross are 100 percent heterozygous for the trait of plant height. What were the most likely genotypes of the parents?

A. [tex] Tt \times tt [/tex]
B. [tex] Tt \times Tt [/tex]
C. [tex] tt \times tt [/tex]
D. [tex] TT \times tt [/tex]

Sagot :

To determine the most likely genotypes of the parents that result in 100 percent heterozygous offspring for the trait of plant height, let's analyze each potential cross mentioned:

1. Cross: [tex]$Tt \times tt$[/tex]

- One parent is heterozygous ([tex]$Tt$[/tex]), and the other parent is homozygous recessive ([tex]$tt$[/tex]).
- The possible offspring from this cross would be:
- [tex]$Tt$[/tex] (from T from the first parent and t from the second parent)
- [tex]$tt$[/tex] (from t from both parents)
- The genotypes of the offspring: [tex]$Tt$[/tex] and [tex]$Tt$[/tex].
- Since all offspring (100%) are heterozygous ([tex]$Tt$[/tex]), this cross is a suitable candidate.

2. Cross: [tex]$Tt \times Tt$[/tex]

- Both parents are heterozygous ([tex]$Tt$[/tex]).
- The possible offspring from this cross would be:
- [tex]$TT$[/tex] (from T from both parents)
- [tex]$Tt$[/tex] (from T from one parent and t from the other parent)
- [tex]$Tt$[/tex] (from t from one parent and T from the other parent)
- [tex]$tt$[/tex] (from t from both parents)
- The genotypes of the offspring: [tex]$TT$[/tex], [tex]$Tt$[/tex], [tex]$Tt$[/tex], and [tex]$tt$[/tex].
- The ratio would be approximately 1:2:1 (25% [tex]$TT$[/tex], 50% [tex]$Tt$[/tex], 25% [tex]$tt$[/tex]), so not all offspring would be heterozygous. This cross cannot result in 100% heterozygous offspring.

3. Cross: [tex]$tt \times tt$[/tex]

- Both parents are homozygous recessive ([tex]$tt$[/tex]).
- The possible offspring from this cross would be:
- [tex]$tt$[/tex] (from t from both parents)
- The genotypes of the offspring: [tex]$tt$[/tex].
- Since all offspring (100%) are homozygous recessive, not heterozygous, this cross is incorrect for the given condition.

4. Cross: [tex]$\pi \times t t$[/tex]

- The genotype [tex]$\pi$[/tex] is not a valid genotype in genetics. This suggestion appears to be erroneous or unrelated to standard genetic notation.
- Thus, we can disregard this option.

From the analysis above, the cross that results in 100% heterozygous ([tex]$Tt$[/tex]) offspring is:

[tex]$Tt \times tt$[/tex].

Therefore, the most likely genotypes of the parents are:

[tex]\[ \boxed{Tt \times tt} \][/tex]