Describe An Individual With The Karyotype Shown XXN GO OD 8 С 10 11 12 88 13 15 14 D TO 16 17 E 18 83 88 888 88 19 20 21 22 F 23 X/Y O A. A Male With Down Syndrome OB. A Female With Down Syndrome O C. A Female With Klinefelter Syndrome O D. A Female With Turner’s Syndrome
The Correct Answer and Explanation is:
Correct Answer: 🅱️ B. A Female With Down Syndrome
Explanation
A karyotype is a visual representation of an individual’s chromosomes, used to identify genetic abnormalities. In a typical human karyotype, there are 46 chromosomes, organized into 23 pairs. Pairs 1 through 22 are autosomes, and pair 23 represents the sex chromosomes (XX for females, XY for males).
Let’s analyze the karyotype provided:
- Sex chromosomes: XX — This indicates the individual is biologically female.
- Chromosome 21: 888 — This is highly indicative of trisomy 21, which means there are three copies of chromosome 21. This genetic abnormality is the cause of Down syndrome.
Why Option B is Correct:
- The individual has two X chromosomes — confirming female sex.
- The presence of three copies of chromosome 21 (trisomy 21) is the hallmark of Down syndrome.
- Therefore, the individual is a female with Down syndrome, which makes Option B the correct answer.
Why Other Options Are Incorrect:
- Option A: A Male With Down Syndrome
Incorrect because the individual has XX, not XY — therefore not male. - Option C: A Female With Klinefelter Syndrome
Incorrect because Klinefelter syndrome typically occurs in males with XXY chromosomes, not in females with XX. - Option D: A Female With Turner’s Syndrome
Incorrect because Turner’s syndrome is characterized by the presence of only one X chromosome (XO), not two.
Summary:
The individual described has an XX sex chromosome pattern, confirming she is female, and three copies of chromosome 21, confirming Down syndrome. Therefore, the best match is B. A Female With Down Syndrome.
