Question

Study the two different crosses given below:

Identify the abnormalities ‘1’ and ‘2’ in the offsprings of given crosses and distinguish between them.

Answer 1

Offspring 1: It has genotype 44 + XO. The abnormality is called Turner syndrome.

Offspring 2: They have genotypes 45 + XY and 45 + XX. The abnormality is called autosomal trisomy.

Difference:

1. Autosomal trisomy, such as Trisomy 21 (Down syndrome), where there are three copies of chromosome 21, is the presence of an extra chromosome in one of the autosomal pairs, whereas Turner Syndrome is caused by monosomy of the X chromosome.
2. Autosomal trisomy affects both males and females, whereas Turner Syndrome only affects females.
3. Individuals with Turner Syndrome may experience learning challenges, infertility, cardiac problems, and small stature. Intellectual disability, facial abnormalities, and other organ-related problems are possible symptoms of Autosomal Trisomy, depending on the particular trisomy (e.g., Down syndrome has distinct facial traits and intellectual impairment).
4. In autosomal trisomy, the failure of nondisjunction results in an extra chromosome, such as an extra copy of chromosome 21 in Down syndrome, whereas in Turner Syndrome, the failure of nondisjunction of sex chromosomes results in a missing X chromosome.