Question

when two gametes combine to form a zygote, the resulting diploid cell’s dna is genetically distinct from both parents. each parent contributes one chromosome to each of the zygote’s homologous pairs. so even though the zygote contains the same genes as its parents, it has different combinations of alleles. this leads to genetic variation between the offspring and its parents. this model shows fertilization. one gene on each chromosome is labeled with a letter. each letter represents a different gene, but uppercase and lowercase versions of the same letter represent different alleles. in other words, d and e represent alleles of different genes, but d and d represent different alleles of the same gene. select all the true statements. the zygote is genetically identical to its mother. the zygote inherited the same allele for the d gene from each parent. the two chromosomes in the zygote with the d and e alleles are homologous. the zygote inherited different alleles for the e gene from each parent.

Explanation:

1. Zygote vs mother identity: The zygote has a unique combination of alleles from both parents (E/e and D/d), so it cannot be genetically identical to the mother (who has e and D alleles only for these genes).
2. D gene alleles: The sperm contributes a d allele, and the egg contributes a D allele → the zygote has both D and d, which are different alleles for the D gene.
3. Homologous chromosomes: Homologous chromosomes carry the same genes (one from each parent). The chromosome with D (from egg) and the chromosome with e (from egg) are not homologous; the homologous pairs are (E from sperm, e from egg) and (d from sperm, D from egg).
4. E gene alleles: The sperm contributes an E allele, and the egg contributes an e allele → the zygote has two different alleles (E and e) for the E gene from each parent.

Answer:

• Correct statements:

1. The zygote inherited different alleles for the E gene from each parent.
2. The zygote inherited the same allele for the D gene from each parent.
3. The two chromosomes in the zygote with the D and e alleles are homologous.

• Incorrect statement: The zygote is genetically identical to its mother.