Question
- Define and interpret karyotypes (genetic anomalies to know:
Down’s, Turner’s and Klinefelter’s)
Down’s, Turner’s and Klinefelter’s)
Ask by Christensen Byrd. in the United States
Mar 16,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
Karyotypes and Genetic Anomalies
-
Down’s Syndrome (Trisomy 21):
- Definition: An extra copy of chromosome 21.
- Karyotype:
for females, for males. - Characteristics: Developmental delays, distinctive facial features, and potential heart defects.
-
Turner’s Syndrome:
- Definition: Absence of one X chromosome in females.
- Karyotype:
. - Characteristics: Short stature, ovarian dysfunction, and cardiovascular and skeletal abnormalities.
-
Klinefelter’s Syndrome:
- Definition: Extra X chromosome in males.
- Karyotype:
. - Characteristics: Reduced testosterone, infertility, and possible learning difficulties.
Each karyotype indicates a specific chromosomal abnormality that affects development and health.
Solution
Step 1: Understanding Karyotypes
A karyotype is an organized profile of an individual’s chromosomes. It displays the number, size, and shape of chromosomes in a cell, which helps in identifying chromosomal anomalies. Anomalies occur when there is an abnormal number or structure of chromosomes.
Step 2: Down Syndrome (Trisomy 21)
- Definition: Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21.
- Karyotype Interpretation:
- For females, the typical karyotype is represented as
. - For males, the karyotype is
.
- For females, the typical karyotype is represented as
- Key Points:
The extra chromosome leads to developmental delays, characteristic facial features, and potential heart defects. The presence of three copies of chromosome 21 (trisomy) distinguishes this condition.
Step 3: Turner’s Syndrome
- Definition: Turner’s syndrome results from the complete or partial absence of one of the X chromosomes in females.
- Karyotype Interpretation:
- The most common karyotype is
, indicating a total of 45 chromosomes instead of the usual 46, with a single X chromosome.
- The most common karyotype is
- Key Points:
Individuals with Turner’s syndrome are typically phenotypically female but may exhibit short stature, ovarian dysfunction, and certain cardiovascular and skeletal abnormalities.
Step 4: Klinefelter Syndrome
- Definition: Klinefelter syndrome is a chromosomal disorder affecting males, characterized by the presence of an extra X chromosome.
- Karyotype Interpretation:
- The most common karyotype is
, which means there are 47 chromosomes including two X chromosomes and one Y chromosome.
- The most common karyotype is
- Key Points:
Males with Klinefelter syndrome may have reduced testosterone levels, infertility, and sometimes learning difficulties or other developmental issues. The presence of an extra X chromosome contributes to these manifestations.
Each of these karyotypes shows a specific chromosomal alteration that has significant effects on the development and clinical features of the individual.
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Simplify this solution Mind Expander
Karyotyping is like flipping through the pages of a genetic book! It’s a visual representation of an individual’s chromosomes, typically arranged in pairs according to size and shape under a microscope. A karyotype can reveal genetic anomalies: for instance, Down syndrome often results from an extra copy of chromosome 21 (trisomy 21), while Turner syndrome is characterized by a missing or incomplete X chromosome (45, X0), typically seen in females. Klinefelter syndrome occurs when males have an extra X chromosome (47, XXY), leading to a variety of physical and reproductive characteristics.
In the real world, karyotypes play a crucial role in prenatal screening and fertility treatments. They can help identify genetic disorders early, allowing parents to make informed decisions during pregnancy. Many couples facing infertility seek karyotyping to understand any underlying genetic issues that may be affecting their chances of conception. So, whether you’re expecting or exploring, karyotyping provides valuable insights into your genetic health!
