Question

Study the two different crosses given below: Identify the abnormalities '1' and '2' in the offsprings of given crosses and distinguish between them.

Accepted Answer

1 = Turner's Syndrome (44 + XO) 2 = Down's Syndrome (45 + XY / 45 + XX) Turner's Syndrome Down's syndrome / Trisomy --- --- Absence of one of the X chromosome 45 with XO Trisomy 21 ^st chromosome / autosomal chromosome extra Sterile female Sterile male or sterile female Rudimentary ovaries / lack of secondary sexual characters / Short stature and underdeveloped feminine character Affected are short statured with small round head / furrowed tongue / physical, psychomotor and mental development is retarded / partially open mouth / broad flat face / any other relevant symptoms

Study the two different crosses given below : Identify the abnormalities '$\displaystyle 1$' and '$\displaystyle 2$' in the offsprings of given crosses and distinguish between them.

Marking-scheme solution

More from Principles of Inheritance and Variation

Turner's Syndrome	Down's syndrome / Trisomy
Absence of one of the X chromosome $\displaystyle 45$ with XO	Trisomy $\displaystyle 21 ^{st}$ chromosome / autosomal chromosome extra
Sterile female	Sterile male or sterile female
Rudimentary ovaries / lack of secondary sexual characters / Short stature and underdeveloped feminine character	Affected are short statured with small round head / furrowed tongue / physical, psychomotor and mental development is retarded / partially open mouth / broad flat face / any other relevant symptoms