NEET PG DENTAL EXAM

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EMBRYOLOGY

CHROMOSOMES AND CELL DIVISIONS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Genes (like the OCA2 genes for eye color) are located on different chromosomes and in different places on chromosomes for every human.
A
Yes
B
No
C
Either A or B
D
None of the above
Explanation: 

Detailed explanation-1: -Several common variations (polymorphisms) in the OCA2 gene reduce the amount of functional P protein that is produced. Less P protein means that less melanin is present in the iris, leading to blue eyes instead of brown in people with a polymorphism in this gene.

Detailed explanation-2: -During the first studies to classify genes for eye color, OCA2 was believed to be the dominating factor for eye color determination. Within the last couple of years, HERC2, an ubiquitin ligase-coding region, has been linked more strongly to eye color. Both genes are located on chromosome 15. OCA2 ranges from 15q11.

Detailed explanation-3: -Variants in the OCA2 gene disrupt the normal production of melanin, which reduces coloring of the hair, skin, and eyes and affects vision. The region of chromosome 15 containing the OCA2 gene is often deleted in individuals with Prader-Willi syndrome.

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