Question

Identify a human disorder with developmental limitations that results from changes in chromosome number. Explain how nondisjunction leads to changes in chromosome number.

Answer 1

Answer:

The Klinefelter syndrome is caused by the presence of one extra X chromosome (i.e., XXY males). Developmental limitations of this genetic disorder include: reduced muscle mass, neurodevelopmental problems, hypogonadism, etc. Abnormal chromosome numbers (known as aneuploidies) are usually caused by the nondisjunction of homologous chromosomes during Anaphase I or the nondisjunction of sister chromatids during Anaphase II

Explanation:

The Klinefelter syndrome is the most common sex chromosomal disorder in males, which is caused by the presence of an extra X chromosome (i.e., males with a XXY karyotype). This genetic disorder has many effects on development, including small testes (hypogonadism), weaker muscles, longer arms and legs, larger breasts than normal, infertility, immature development of secondary male sex features, cognitive problems (e.g., speech and language delays), etc. A chromosomal disorder occurs when chromosome pairs or chromatids fail to separate during meiosis, thereby producing cells (gametes) with more or fewer chromosomes than normal, a phenomenon known as aneuploidy.