Question

9. Different genes are located on different kinds of genetic elements - autosomes, W chromosomes, the mitochondrial genome, etc. Different elements are inherited in different ways, so different offspring inherit different elements from different parents. For each case, answer "both parents', 'mother', 'father, or 'neither parents. For instance, sons inherit autosomal genes from both parents, but sons inherit W chromosome genes from neither parent (because males are ZZ, and don't have a W chromosome...) (1 point per answer) Sons inherit Y chromosome genes from: Sons inherit mitochondrial genes from: Daughters inherit mitochondrial genes from: Daughters inherit z chromosome genes from: 10. Consider the simplified scenario for genetic determinants of height in humans, where there are three genes (A/B/C) with varying numbers of alleles (3/3/2) affecting height, and with different effects in males and females. (Assume additive contributions, thus the effect of having genotype A1 A2 is +0.1" + +0.25 +0.3"). Average height for men and women is 69" and 64". Gene Allele li 2 3 B 1 12 3 C1 2 Male effect 1.0.1 -02 |-1.3 1-05 -04 -0.1 Female effect +0.1 +0.2 -1.5 - 13 1-0.2 0.1 1.15 .0.1 What is the expected height for a male with genotype ATA1B2B2C1C2 (3 points)? 11. Consider a cross between two heterozygotes. What is the probability that their first offspring has dominant phenotype? (2 points) What is the probability that their first offspring has dominant phenotype and the second offspring also has the dominant phenotype? (2 points) What is the probability that out of their first offspring, one has dominant phenotype and one has recessive phenotype? (2 points)

Answer 1

Answer to question 9

Sons inherit Y chromosome gene from father.In XY type of sex determination, in males an X chromosome is present but its counter part is distinctly smaller called Y chromosome.Females have a pair of X chromosome.Sex of the child is determined by father.when Y chromosome from fther and X chromosome from mother fuse together a male offspring is produced.When an X from mother and another X from father fuse together a female offspring is produced.Examples of XY type of sex determination are man and fruit fly.

Sons inherit mitochondrial gene from mother.Mitochondrial genomes are small circular DNA present in the mitochondria.In humans sperm does not contain cytoplasm.Sperm structure consist of head,neck,middle piece and a tail.Head contains nucleus.In ovum there is nucleus and cytoplasm as well.Mitochondria is a cytoplasmic organelle.That is why mitochondrial gene comes exclusively from mother to offspring.

Daughters inherit mitochondrial gene from mother due to the same reason explained earlier.

Daughters inherit Z chromosomal gene from father.In birds the sex determination is ZW type.Male carries two Z chromosomes and female carries a Z and W chromosomes.Sex of offspring is determined by mother.When Z from father and W from mother fuse together a female offspring is produced whereas one Z from each parent fuse together to form a male offspring.