also located on the X chromosome is a gene that codes for deafness. This gene is recessive. a black female cat that is heterozygous for deafness (Dd) is crossed with a yellow cat that is not deaf What is the Punnet Square . and must use two letters on the x chromosome
To determine the Punnett Square for this cross, we need to consider that the gene for deafness is located on the X chromosome. The black female cat is heterozygous for deafness (Dd) and the yellow cat is not deaf.
To construct the Punnett Square, we will assign the X chromosome alleles from both parents. Let's represent the allele for the black cat as Xd and the allele for the yellow cat as X (normal hearing).
The possible combinations of the X chromosomes for the offspring are as follows:
Female Offspring:
- XdX (heterozygous for deafness like the black female)
- XDX (normal hearing)
Male Offspring:
- XDY (normal hearing)
Now, let's organize these combinations into a Punnett Square:
| Xd | XD |
-------------------------
XDX | XdXDX | XdXD |
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XDY | XDXDY | XDY |
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In this Punnett Square, we have four possible combinations of X and Y chromosomes, representing the possible genotypes of the offspring.
To summarize:
- There is a 25% chance of having a deaf female cat (XdX).
- There is a 25% chance of having a female cat with normal hearing (XDX).
- There is a 50% chance of having a male cat with normal hearing (XDY).
Please note that this Punnett Square assumes Mendelian inheritance patterns and does not take into account other potential genetic or environmental factors that may influence the expression of deafness.