Question

Read the following statements carefully and select the correct option.
A. Sanger is credited for developing the method for determination of amino acid sequence in proteins.
B. Repeated sequence makes up a very large portion of the human genome.
C. The functions are unknown for over 50% of discovered genes.

• A. Only (A)
• B. Only (B) and (C)
• C. Only (A) and (B)
• D. (A), (B) and (C)

Answer 1

Answer: (D)

Fredrick Sanger has invented the method for sequencing of protein and nucleic acids which is used in the HGP. In 1945, he developed a three-stage method for the identification, quantitative measurement and characterizing of the terminal amino acids in insulin. This involved treating the protein with FDNB, subjecting it to acid hydrolysis and then separating the coloured compounds with chromatography.
1-Fluoro-2,4-dinitrobenzene or Sanger's reagent (also called 'dinitrofluorobenzene' or DNFB or FDNB) is the chemical that reacts with the N-terminal amino acid of polypeptides, and this is helpful for sequencing proteins.
By analysis of the human genome, we have found that a large portion of the genome is non-coding and made up of a repeated sequence of DNA called a 'satellite DNA'. The functions of half of the genes are yet to be explored. The human genome contains 3.1647 billion base pairs. The total number of genes is about 30,000. Previously it was believed that human beings carry 80,000 - 1,40,000 genes. The function of over half of the discovered genes is unknown. Less than 2% of the genome contains coded information for protein synthesis. Part of DNA, which contains small sequences in repetition, is called satellite DNA. Satellite DNA is of several types. One of them is moderately repetitive sequences of 150-300 base pairs long.