Molecular biology techniques have led to molecular systematics – creating phylogenetic tree hypotheses based on DNA. You did this yourself in class, creating a phylogenetic tree that compared some major Phyla of animals. What is the basic concept behind using DNA to create these trees – what assumptions are made? Do you think this is a reasonable way to study evolutionary history of living things? Explain.
Ans: The basic concept behind using DNA to create phylogenetic trees is that as the organisms evolve and diverge, their DNA sequences accumulate mutations. Scientists compare these mutations using sequence alignments to reconstruct evolutionary history.
It has been suggested that the amount of change that takes place in DNA over time can act as a molecular clock, gauging how much evolutionary time has passed. The clock is set by first examining geological and historical records to determine how long two species have been physically separated.
The main assumption which is used in molecular dynamics is evolutionary clock hypothesis which suggest that Genes are thought to evolve and mutate at a constant, predictable rate, by examination of the number of molecular changes that have occurred between those species over that known time, a time frame of change can be established. Some other assumptions are that sequence must be aligned; classification must correspond to phylogenetic descent, all valid taxa must be monophyletic ( all the descendants shared common ancestory).
This type of evolutionary relationship has soem advantages and some disadvantages. Advantages includes that it allows the examination of how species have changed over evolutionary time and the relationships between species that have no common physical characteristics. But it has some disadvantages too like it is assumptions sensitive and it does not taking epigentic changes under consideration as we all know epigenetic changes are heritable changes that does not involve genetic alteration. So i think that this method is suitable for evolutionary study because as we know that this era is digital era and we have so much of data related to the genomic sequences of different different organisms so with the help of this tool we will be able to study the evolutionary relationship between different different organisms.
Molecular biology techniques have led to molecular systematics – creating phylogenetic tree hypotheses based on DNA....
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