DG8-genomic sequencing

• In genomic sequencing the sequence of nucleotide bases can be determined for individual genes and entire genomes
• Many genomes have been sequenced, particularly of disease-causing organisms, pest species and species that are important model organisms for research
• Genomes from different species are often compared
• comparison of genomes reveals that many genes are highly conserved across different organisms
• Bioinformatics is the use of computer analysis and statistical analysis to compare genomic sequence data
• Computer programs can be used to identify base sequences similar to known genes
• Phylogenetics is the study of the evolutionary relatedness among groups of organisms
• Comparison of sequences provides evidence of the three domains of life- bacteria, archaea and eukaryotes
• The data from genomic sequencing is used to work out the evolutionary history and relationships of different species
• Species with more similarity in their genomes are more closely related
• A phylogenetic tree can be read like a map of evolutionary history
• The vertical lines, called branches represent the lineage
• Phylogenetics can be used to work out:

  • lineage- the exact sequence in which species can be traced back through ancestral populations
  • sequence divergence- how and when lineages diverged from common ancestry
• A molecular clock is a measure of evolutionary change over time at the molecular level
• Molecular clocks use sequence data to measure the number of mutations that accumulate in a DNA sequence over time to show when species diverged during evolution
• Molecular clocks assume that DNA sequences and amino acid sequences mutate at a constant rate
• Therefore, differences in sequence data between species indicate the time of divergence from a common ancestor
• Evidence from phylogenectics and molecular clocks has been used to determine the main sequence of events in evolution
• Sequence data (from phylogenetics), along with fossil evidence, has allowed biologists to determine the main sequence of events in the evolution of life.
• • cells
  • last universal ancestor
  • prokaryotes
  • photosynthetic organisms
  • eukaryotes
  • multicellular life
  • animals
  • verebrates
  • land plants
• Medical researchers may use genomic information to compare the DNA of individuals who bear an inherited disease with those who are unaffected
• Differences between their genomes may reveal the presise mutation and cause of their condition
• An individual's genome can be analysed to predict the likelihood of developing certain diseases
• 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.

  This is called personalised medicine