I am having trouble wording this question.
Describe the differences in the outcomes for a dihybrid cross ifgenes are:
a. completely linked
b. completely unlinked
c. incompletely linked.
To describe the differences in the outcomes for a dihybrid cross based on the level of linkage between genes, we need to understand what is meant by "completely linked," "completely unlinked," and "incompletely linked."
a. Completely linked genes: When genes are completely linked, they are located very close to each other on the same chromosome, thus they tend to be inherited together. As a result, during a dihybrid cross, the two genes will segregate together and show no recombination between them. Offspring will inherit only the original combinations of alleles from the parental generation, causing no new combinations to be formed.
b. Completely unlinked genes: When genes are completely unlinked, they are located on different chromosomes or are far apart on the same chromosome. In this case, during a dihybrid cross, the two genes segregate independently of each other. This means that new combinations of alleles can be formed due to the random assortment of the chromosomes during meiosis. Offspring will show a wide variety of different combinations of alleles for the two genes.
c. Incompletely linked genes: Incompletely linked genes are located on the same chromosome but are not close enough together to be completely linked. During a dihybrid cross involving incompletely linked genes, although some of the offspring will inherit the parental combinations of alleles, there will also be a certain proportion of offspring that show new combinations resulting from recombination events. Recombination occurs when homologous chromosomes exchange genetic material during meiosis, leading to the formation of new combinations of alleles.
To summarize:
- Completely linked genes result in no recombination and offspring show only the parental combinations.
- Completely unlinked genes result in independent assortment and offspring show a wide variety of different allele combinations.
- Incompletely linked genes can result in both parental and non-parental combinations due to the occurrence of recombination events during meiosis.
These differences in outcomes between completely linked, completely unlinked, and incompletely linked genes during a dihybrid cross can be understood by considering the level of genetic linkage and recombination between the genes involved.