In genomic sequencing the sequence of nucleotide bases can be determined for individual genes and entire genomes.

• Computer programs can be used to identify base sequences by looking for sequences similar to known genes.

Comparison of genomes from different species.

• To compare sequence data, computer and statistical analyses (bioinformatics) are required.

Comparison of genomes reveals that many genes are highly conserved across different organisms.

• Many genomes have been sequenced, particularly of disease-causing organisms, pest species and species that are important model organisms for research.

Evidence from phylogenetics and molecular clocks to determine the main sequence of events in evolution. 

The sequence of events can be determined using sequence data and fossil evidence.

• Phylogenetics is the study of evolutionary history and relationships.

• Use of sequence data to study the evolutionary relatedness among groups of organisms. 

• Sequence divergence is used to estimate time since lineages diverged.

Comparison of sequences provides evidence of the three domains of life — bacteria, archaea and eukaryotes.

• Use of sequence data and fossil evidence to determine the main sequence of events in evolution of life: cells, last universal ancestor, prokaryotes, photosynthetic organisms, eukaryotes, multicellularity, animals, vertebrates, land plants.

• Molecular clocks are used to show when species diverged during evolution. 

• They assume a constant mutation rate and show differences in DNA sequences or amino acid sequences. 

• Therefore, differences in sequence data between species indicate the time of divergence from a common ancestor.

An individual’s genome can be analysed to predict the likelihood of developing certain diseases.

Pharmacogenetics and personalised medicine.

• Pharmacogenetics is the use of genome information in the choice of drugs.

• An individual’s personal genome sequence can be used to select the most effective drugs and dosage to treat their disease (personalised medicine).