Video Transcript
Phylogeny is the study of evolutionary relationships among different groups of organisms. Which of the following best describes how the Human Genome Project has helped the science of phylogeny? (A) By comparing the ratio between coding and noncoding regions of a living organism. (B) By comparing the human genome with those of other living organisms. (C) By identifying the noncoding regions of genes. (D) By identifying common ancestors in a genetic map.
This question mentions phylogeny, which is the study of how organisms are related through evolution. In order to answer how the Human Genome Project helped establish evolutionary relationships, let’s discuss what this project entailed.
The Human Genome Project was an international endeavor that cost nearly three billion dollars and spanned 13 years. Its main goal was to determine the sequence of all of our DNA, also known as our genome, and to map the location of all our genes. After sequencing the genome, we found that our genome contains over three billion nucleotides and over 20,000 genes. So how might sequencing the human genome help with determining evolutionary relationships for phylogeny?
With the technology we developed using the Human Genome Project, we are now able to sequence the genomes of other organisms as well and compare them. We can see that this portion of the chimpanzee and human genome sequence are very similar, with only a single nucleotide difference. In fact, the genome sequence of humans and chimpanzees is almost 99 percent identical. This suggests that we share a recent common ancestor with chimpanzees.
On the other hand, if we compare the human genome sequence to mice, we find that they’re less similar, at about 85 percent. This suggests that humans share a more recent common ancestor with chimpanzees compared to mice. By sequencing genomes of organisms and comparing the sequences, we can establish evolutionary relationships.
Getting back to our question, the option that best describes how the human genome project has helped the science of phylogeny is given by answer choice (B): by comparing the human genome with those of other living organisms.
