1
USMLE
USMLE Genetics Exam Questions
with Correct Verified Answers
Latest Update (2024/2025)
Guaranteed Pass
1. What is the Hardy-Weinberg Equation? - ANS ✓P squared + 2PQ +
Q Squared =1
2. What do P and Q stand for in the HQ equation? - ANS ✓The
frequency of allele 1 (P) and allele 2(Q)
3. What is Psquared in the HQ equilibrium? - ANS ✓The frequency of
genotype allele 1 and allele1
2pq is frequency of genotype allele 1 and allele 2 (heterzogote prevalaence)
etc...
4. Most common cause of loss of pregnancy? - ANS ✓Chromosomal
abnormality
5. What is Euploidy? - ANS ✓When a cell has a multiple number of 23
chromosomes...46, 69 92...
6. What is a haploid cell? - ANS ✓One that has 1 member of each
chromosome.
USMLE Genetics
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USMLE
7. What is a diploid cell? - ANS ✓One that has 2 copies of each pair of
chromosomes
8. Are triploid or tetra ploidy compatible with life? - ANS ✓No
9. What is aneuploidy? - ANS ✓A cell having extra or missing
chromosomes that are not a multiple of 23
10. Are all autosomal monosomies lethal? - ANS ✓YES
11. Which trisomies are compatible with life? - ANS ✓Trisomy
13, 18 and 21...three copies of 13, 18 or 21 respectively
12. What is the karyotype of Kleinfelter syndromes? - ANS
✓XXY or XXXY
13. What is the idea of mosaicism? - ANS ✓When there are two
different cell types within one persons body.... Say when half of the
cells of a body are normal, and half have XXY, or half have 3 copies of
Ch21.
14. What is the most common cause aneuploidy? - ANS
✓Nondisjunction during meiosis either 1 or 2.
15. Why is an 'older mother' defined as being 35 or older? -
ANS ✓Because before that time, the risk of termination of pregnancy
by amniocentesis is 1/200 but the risk if a generic disease is not, so
amniocentesis is not generally done. After that age, the risk of a
disease IS greater than 1/200 so amniocentesis is a good option.
USMLE Genetics
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USMLE
16. What is a reciprocal translocation? - ANS ✓When two non-
homologous chromosomes exchange genetic information--- 9:22,
8:14 etc.
17. On USMLE, what is the likely reason that a couple might
have had multiple pregnancy losses and a Down Syndrome
Child? - ANS ✓A Robertsonian Translocation has likely occurred in
one of the parents germ cells...When these cells pair up in ADJACENT
segregation, one of the sets is likely to have 1 normal Ch21 and
another Ch with partial Ch21 material on it.
18. What is a Robertsonian Translocation? - ANS ✓When there
is non-reciprocal chromosomal translocations of acrocentric
chromosomes 13, 14, 15, 21 or 22. The small p arms of two
chromosomes get broken off and disappear, the remaining q arms get
joined together.
19. What type of chromosomal segregation can occur in
Robertsonian or reciprocal translocations that still cause
normal offspring when paired up? - ANS ✓Alternative segregation
20. What type of DELETION occurs in Prader WIlli or
Angelman syndromes? - ANS ✓Interstitial deletion of part of the
chromosome (in the middle portion of the chromosome) in addition
to the normal imprinting.
21. What type of deletion occurs in Cri-du-chat syndrome? -
ANS ✓A terminal deletion of the short arm, p arm of chromosome 5
USMLE Genetics
USMLE
USMLE Genetics Exam Questions
with Correct Verified Answers
Latest Update (2024/2025)
Guaranteed Pass
1. What is the Hardy-Weinberg Equation? - ANS ✓P squared + 2PQ +
Q Squared =1
2. What do P and Q stand for in the HQ equation? - ANS ✓The
frequency of allele 1 (P) and allele 2(Q)
3. What is Psquared in the HQ equilibrium? - ANS ✓The frequency of
genotype allele 1 and allele1
2pq is frequency of genotype allele 1 and allele 2 (heterzogote prevalaence)
etc...
4. Most common cause of loss of pregnancy? - ANS ✓Chromosomal
abnormality
5. What is Euploidy? - ANS ✓When a cell has a multiple number of 23
chromosomes...46, 69 92...
6. What is a haploid cell? - ANS ✓One that has 1 member of each
chromosome.
USMLE Genetics
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USMLE
7. What is a diploid cell? - ANS ✓One that has 2 copies of each pair of
chromosomes
8. Are triploid or tetra ploidy compatible with life? - ANS ✓No
9. What is aneuploidy? - ANS ✓A cell having extra or missing
chromosomes that are not a multiple of 23
10. Are all autosomal monosomies lethal? - ANS ✓YES
11. Which trisomies are compatible with life? - ANS ✓Trisomy
13, 18 and 21...three copies of 13, 18 or 21 respectively
12. What is the karyotype of Kleinfelter syndromes? - ANS
✓XXY or XXXY
13. What is the idea of mosaicism? - ANS ✓When there are two
different cell types within one persons body.... Say when half of the
cells of a body are normal, and half have XXY, or half have 3 copies of
Ch21.
14. What is the most common cause aneuploidy? - ANS
✓Nondisjunction during meiosis either 1 or 2.
15. Why is an 'older mother' defined as being 35 or older? -
ANS ✓Because before that time, the risk of termination of pregnancy
by amniocentesis is 1/200 but the risk if a generic disease is not, so
amniocentesis is not generally done. After that age, the risk of a
disease IS greater than 1/200 so amniocentesis is a good option.
USMLE Genetics
, 3
USMLE
16. What is a reciprocal translocation? - ANS ✓When two non-
homologous chromosomes exchange genetic information--- 9:22,
8:14 etc.
17. On USMLE, what is the likely reason that a couple might
have had multiple pregnancy losses and a Down Syndrome
Child? - ANS ✓A Robertsonian Translocation has likely occurred in
one of the parents germ cells...When these cells pair up in ADJACENT
segregation, one of the sets is likely to have 1 normal Ch21 and
another Ch with partial Ch21 material on it.
18. What is a Robertsonian Translocation? - ANS ✓When there
is non-reciprocal chromosomal translocations of acrocentric
chromosomes 13, 14, 15, 21 or 22. The small p arms of two
chromosomes get broken off and disappear, the remaining q arms get
joined together.
19. What type of chromosomal segregation can occur in
Robertsonian or reciprocal translocations that still cause
normal offspring when paired up? - ANS ✓Alternative segregation
20. What type of DELETION occurs in Prader WIlli or
Angelman syndromes? - ANS ✓Interstitial deletion of part of the
chromosome (in the middle portion of the chromosome) in addition
to the normal imprinting.
21. What type of deletion occurs in Cri-du-chat syndrome? -
ANS ✓A terminal deletion of the short arm, p arm of chromosome 5
USMLE Genetics
