Question

In open angle glaucoma, cell death in the optic nerve prevents fluid from draining out of the eye. The pressure from the constrained fluid builds up in the eyeball, eventually impairing peripheral vision. Surgery, laser treatment, or drugs can relive the pressure. Vision is usually not noticeably affected until after age 40. Several mutations in a gene on Chromosome 1, GLC1A, cause this condition. However, some polymorphisms in the gene do not affect the phenotype.

1. How can a change in a gene's sequence not alter the protein product?

Answer 1

How can a change in a gene's sequence not alter the protein product?

Single Nucelotide polymorphisms (SNPs) causes variation in DNA sequence among individuals. SNPs can include transversions, transitions etc and contribute to genetic diversity.

On one hand, SNPs can alter the encoded amino acid and therefore affect the phenotype. On the other hand, it is also possible that SNPs causes silent mutations that doesnot alter the phenotype or can occur in non coding regions of the DNA that doesnt cause any change to the phenotype of the individual.

Silent mutations doesnt alter the phenotype of the individual since these s donot change the amino acid composition due to the generacy of the genetic code (synonymous SNPs)