Question

In the accompanying art you see a table with the actual number of offspring that resulted from a dihybrid cross. The numbers do not show the 9:3:3:1 ratio predicted. One phenotype occurred more than predicted; another occurred less. The reason could be because ______.

A) of errors in mitosis
B) some of the alleles were linked
C) some of the alleles were sex-linked
D) of polygenic inheritance

Answer 1

In the accompanying art you see a table with the actual number of offspring that resulted from a dihybrid cross. The numbers do not show the 9:3:3:1 ratio predicted. One phenotype occurred more than predicted; another occurred less. The reason could be because of errors in mitosis. Option A is correct.

Step-by-step explanation:

The deviation from the predicted 9:3:3:1 ratio in a dihybrid cross is attributed to errors in mitosis, the cellular division process. Mitotic errors can disrupt the expected distribution of alleles, causing certain phenotypes to be overrepresented or underrepresented. These errors might include chromosome missegregation or non-disjunction, leading to an uneven distribution of genetic material to daughter cells.

As a consequence, the observed phenotypic ratios differ from the Mendelian expectations. Understanding the impact of mitotic errors on genetic outcomes is crucial in comprehending the complexities of inheritance patterns and the variations that can arise in offspring phenotypes. Hence, option A is correct.