Investigating diversity DNA analysis

Question 1

DNA is extracted from the nuclei of cells taken from an organism
DNA can be extracted from blood or skin samples from living organisms or from fossils
The extracted DNA is processed, analysed and the base sequence is obtained
The base sequence is compared to that of other organisms to determine evolutionary relationships
The more similarities there are in the DNA base sequence, the more closely related

The differences between the nucleotide sequences (DNA) of different individuals can provide a lot of information:

Answer 1

The more similar the sequence the more closely related the species are

Two groups of organisms with very similar DNA will have separated into separate species more recently than two groups with less similarity in their DNA sequences

DNA sequence analysis and comparison can also be used to create family trees that show the evolutionary relationships between species

Question 2

Mitochondrial DNA

When analysing DNA from the mitochondria is is important to remember that:

Answer 2

A zygote only contains the mitochondria of the egg and none from the sperm so only maternal mitochondrial DNA is present in a zygote

There is no crossing over that occurs in mtDNA so the base sequence can only change by mutation

The lack of crossing over in mtDNA has allowed scientists to research the origins of species, genetic drift and migration events

This mtDNA of this species is then used as a baseline for comparison with the mtDNA of other species