Consider a day at zootwo friends go to visit the chimpanzee

Consider a day at zoo-two friends go to visit the chimpanzee exhibit. Thinking about their genomic sequence, how do the genomes of the genomes of the two friends differ from each other? How do the genomes of the friends differ from the genome of the chimpanzee?

Solution

1. Genome difference of two non related persons is about 1 in 1200 to 1500 DNA bases. The variations mostly very small, occur because of substitution of one base by another like T for an A (SNP) or G or deletion of one base both of which may occur because of error during DNA copying. About 90% genome variation occurs because of SNPs( Single Nucleotide Polymorphism).This is how the two friends differed.

Human and chimpanzee evolved from a common ancestor but as they diverged from one another, DNA changes occured separately which mostly involved base pair substitution and duplication. Primary change that occured is change in the chromosome number. Chimpanzees have 24 chromosomes whereas humans have 23 chromosomes.If some base sequences are repeated twice in human and present only once in chimpanzees, then, that extra copy may make a large number of changes in human. Again same base sequence may be present in both but at different places. In that case also different proteins will be produced in two, leading to different reactions. This is how the two friends differed from the chimpanzee.

In the end it can be said that if similarity between two humans is 99.9%, it is 99% between human and chimpanzee.