Q.Give an example of a chromosomal disorder caused due to non-disjunction of autosomes.

Any two: short stature with a flat, broad face and flat nasal bridge; oblique/slanting eyes with an epicanthic fold; a single (simian) palmar crease on short, broad hands; and mild to moderate intellectual disability.

Down's syndrome (trisomy 21) shows characteristic facial, hand and developmental features.

Down's syndrome results from trisomy of chromosome 21 (an extra copy, giving 47 chromosomes instead of 46), usually due to non-disjunction during meiosis in a parent. Characteristic symptoms include: short stature; a flat facial profile with a flat, broad nasal bridge; upward-slanting (oblique) eyes with a prominent epicanthic fold; a short neck; short, broad hands often showing a single transverse (simian) palmar crease; a partially open m …

45, X (also written 44+X or XO) — a total of 45 chromosomes with only a single X chromosome and no Y.

Turner's syndrome results from monosomy of the X chromosome, giving a 45,X karyotype.

Turner's syndrome is a chromosomal disorder caused by the complete or partial absence of one X chromosome in females, arising from non-disjunction during gamete formation. Affected individuals have a karyotype of 45,X (also written 44+X, or informally XO) — that is, the normal 44 autosomes plus only a single X chromosome, instead of the usual two X chromosomes (44+XX) found in normal females. This monosomy results in a total chromosome count of 45 rather than the normal …