Chapter 13, Problem 26A

Summary Introduction

Introduction:

The Human Genome Project (HGP) was undertaken to determine the sequence of nucleotides in human DNA and to identify all its genes. The scientists had to decode the genetic code in the human genome. Although more than 99 percent of all nucleotide sequences are exactly same in all humans, sometimes there are variations that are linked to human diseases.

Answer to Problem 26A

Correct answer :

The correct answer is option C. single nucleotide polymorphisms

Explanation of Solution

Explanation/justification for the correct answer:

Option C. single nucleotide polymorphisms − Variations in specific nucleotides that are linked to human diseases are called single nucleotide polymorphisms or SNPs. These variations in the DNA sequence occur when a single nucleotide in the genome is altered. SNP maps may help scientists identify many genes associated with many genetic disorders.

Hence, this is the correct option.

Explanation for incorrect answer:

Option A. proteomes− Proteomes refer to all the proteins found in a cell. Genes are the primary information storage units whereas proteins are the machines of a cell. So study of functions of proteins is also very important. Variations in specific nucleotides that are linked to human diseases are called single nucleotide polymorphisms or SNPs and not proteomes. Hence, this is not the correct option.

Option B. haplotypes- Just as linked genes are inherited together, genetic variations located close to each other also tend to be inherited together. Such linked variations are called haplotypes. Haplotypes are a cluster of SNPs that are inherited together. Hence, this is not the correct option.

Option D. genomes− The total number of genes in an organism is called genome. Genomes contain all the information needed for an organism to grow and survive. Hence, this is not the correct option.