Question 1

Which of the following best describes the maternal effect in Limnaea peregra (water snails) shell coiling?

Accepted Answer

The phenotype of the offspring is determined by the mother's genotype, regardless of the offspring's or father's genotype.

Question 2

A cross is made between a heterozygous female mouse (XBXb) and a black male mouse (XBY). According to the Lyon hypothesis, what percentage of the progeny is expected to have a variegated coat?

Accepted Answer

50%

Question 3

Which gene is responsible for coating the inactive X chromosome with RNA during X inactivation?

Accepted Answer

Xist

Question 4

In humans, how many Barr bodies would you expect in a cell from an individual with the genotype XXY?

Accepted Answer

$$1$$

Question 5

Which of the following is an example of epigenetic inheritance?

Accepted Answer

Genomic imprinting

Question 6

A dominant maternal effect allele (m+) controls cleavage patterns in Drosophila. If 250 eggs are generated from a cross between flies with a heterozygous genotype, how many eggs are expected to produce sterile female flies?

Accepted Answer

$$31$$

Question 7

Which of the following statements about mitochondrial inheritance in humans is correct?

Accepted Answer

Mitochondrial DNA is inherited strictly from the mother.

Question 8

Which of the following best explains the endosymbiosis theory for the origin of mitochondria and chloroplasts?

Accepted Answer

Mitochondria and chloroplasts originated from bacteria engulfed by ancestral eukaryotic cells, forming a symbiotic relationship.

Question 9

Which of the following is NOT a mechanism of dosage compensation?

Accepted Answer

Tripling expression of X-linked genes in female mammals

Question 10

Which of the following is a key difference between maternal inheritance and maternal effect genes?

Accepted Answer

Maternal effect genes determine the phenotype of the offspring based on the mother's nuclear genotype, while maternal inheritance involves transmission of extranuclear elements like mitochondrial DNA.

Question 11

Which of the following best describes heteroplasmy?

Accepted Answer

The presence of more than one type of organelle genome (mitochondria or chloroplast) in a single cell

Question 12

Which of the following diseases is caused by mutations in mitochondrial DNA and affects the optic nerve?

Accepted Answer

Leber’s hereditary optic neuropathy (LHON)

Question 13

In Saccharomyces cerevisiae, which type of petite mutation demonstrates cytoplasmic transmission and results in all haploid progeny being petite?

Accepted Answer

Suppressive petite

Question 14

Which of the following statements about genomic imprinting is correct?

Accepted Answer

Genomic imprinting is an epigenetic phenomenon that causes genes to be expressed in a parent-of-origin-specific manner.

Question 15

Which of the following best describes the inheritance pattern of chloroplasts in Chlamydomonas?

Accepted Answer

Chloroplasts are inherited from the parent with the mt+ mating type.

Question 16

Which of the following epigenetic modifications is associated with gene silencing?

Accepted Answer

Addition of methyl groups to DNA

Question 17

Which syndrome results from a deletion on maternal chromosome 15 paired with a paternally imprinted chromosome 15?

Accepted Answer

Angelman syndrome

Question 18

Which equation correctly represents the expected number of sterile female flies in a Drosophila cross with a dominant maternal effect allele (m+) and 250 eggs?

Accepted Answer

$$\frac{1}{4} 	imes 125 = 31.25$$

Question 19

Which of the following is a real-world example of horizontal gene transfer?

Accepted Answer

Transfer of antibiotic resistance genes via plasmids between bacteria

Non-Mendelian Inheritance: Maternal Effect, Extranuclear, and Epigenetic Inheritance

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