GENETICS MIDTERM QUICK REVISION
FLASHCARDS 2026
◉ In mammals, which sex is heterogametic?
Answer: Males (XY).
◉ In birds, which sex is heterogametic?
Answer: Females (ZW).
◉ What does Turner syndrome (XO) indicate about sex
determination?
Answer: At least one X is required; no Y results in a female
phenotype.
◉ What does Klinefelter syndrome (XXY) indicate about sex
determination?
Answer: The presence of a Y chromosome results in a male
phenotype.
◉ What determines maleness in humans?
Answer: The presence of the Y chromosome, specifically the SRY
gene.
,◉ What is the function of the SRY gene?
Answer: It initiates testis development.
◉ What is the phenotype of an XY individual without the SRY gene?
Answer: Female.
◉ What is the phenotype of an XX individual with the SRY gene?
Answer: Male.
◉ What causes androgen insensitivity syndrome (AIS)?
Answer: A mutation in the androgen receptor.
◉ Why are individuals with AIS phenotypically female?
Answer: Their cells cannot respond to testosterone.
◉ What are parental outputs of meiosis?
Answer: Gametes with original allele combinations.
◉ What are recombinant outputs of meiosis?
Answer: Gametes with new allele combinations due to crossing over.
, ◉ How do you identify parental vs. recombinant phenotypes in
offspring?
Answer: The most frequent phenotypes are parental; the least
frequent are recombinant.
◉ What does linked gene notation (e.g., wM / Wm) represent?
Answer: It shows which alleles are located together on the same
chromosome.
◉ Why is a testcross useful in studying linkage?
Answer: It reveals the gametes produced by a heterozygote.
◉ What genotype is used in a linkage testcross?
Answer: Homozygous recessive.
◉ How is recombination frequency calculated?
Answer: (Number of recombinants ÷ total offspring) × 100.
◉ What does recombination frequency measure?
Answer: The genetic distance between genes.
◉ What is the definition of 1 cM (centimorgan)?
FLASHCARDS 2026
◉ In mammals, which sex is heterogametic?
Answer: Males (XY).
◉ In birds, which sex is heterogametic?
Answer: Females (ZW).
◉ What does Turner syndrome (XO) indicate about sex
determination?
Answer: At least one X is required; no Y results in a female
phenotype.
◉ What does Klinefelter syndrome (XXY) indicate about sex
determination?
Answer: The presence of a Y chromosome results in a male
phenotype.
◉ What determines maleness in humans?
Answer: The presence of the Y chromosome, specifically the SRY
gene.
,◉ What is the function of the SRY gene?
Answer: It initiates testis development.
◉ What is the phenotype of an XY individual without the SRY gene?
Answer: Female.
◉ What is the phenotype of an XX individual with the SRY gene?
Answer: Male.
◉ What causes androgen insensitivity syndrome (AIS)?
Answer: A mutation in the androgen receptor.
◉ Why are individuals with AIS phenotypically female?
Answer: Their cells cannot respond to testosterone.
◉ What are parental outputs of meiosis?
Answer: Gametes with original allele combinations.
◉ What are recombinant outputs of meiosis?
Answer: Gametes with new allele combinations due to crossing over.
, ◉ How do you identify parental vs. recombinant phenotypes in
offspring?
Answer: The most frequent phenotypes are parental; the least
frequent are recombinant.
◉ What does linked gene notation (e.g., wM / Wm) represent?
Answer: It shows which alleles are located together on the same
chromosome.
◉ Why is a testcross useful in studying linkage?
Answer: It reveals the gametes produced by a heterozygote.
◉ What genotype is used in a linkage testcross?
Answer: Homozygous recessive.
◉ How is recombination frequency calculated?
Answer: (Number of recombinants ÷ total offspring) × 100.
◉ What does recombination frequency measure?
Answer: The genetic distance between genes.
◉ What is the definition of 1 cM (centimorgan)?
