Explain how DNA sequencing has clarified the
relationships of ancient and modern human lineages.
The molecular clock-- The technique that uses the mutation rate of biomolecules (usually nucleotide sequences for DNA or amino acid sequences for proteins) to deduce the time in the previous history when two or more life forms diverged, is represented in the figured term called the molecular clock.
The Phylogenetic tree – it is a diagrammatic representation evolutionary relationship among organism and reflects and the hypothesis that how species are evolved from each other from a common ancestor. A phylogenetic tree can be made on the basis of various information but DNA sequence is widely used as it is cheap nowadays and easy to get DNA sequence and most important DNA possess more information to make an accurate tree. Some change in DNA sequences does not cause a change in proteins.
DNA sequencing is a method by which we get to know the sequence of the genes in a genome of an organism. To construct a tree based on DNA sequencing, we compare the DNA sequences which we get from DNA sequencing of different species.
Evolutionarily related species at a time had a common ancestor and before they diverge into different species, they had exactly the same DNA. As a species evolve and diverge. The changes accumulate in DNA sequence. And this accumulated changes in the DNA sequence can be used to predict how closely two species are.
The first up all different DNA sequences from different species are aligned together which we want to compare but it should be sure that we are comparing the same gene. This alignment is done by computer programs. By comparing this alignment, we get to know that how many sequences similar they are to each other. If there is not much difference they are probably closely related. And if much difference in their DNA sequence it means they might be more distant relatives
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