DNA Technology, Classification and Diversity

What is genome sequencing?

• Advances in genome sequencing have meant that the entire base sequence of an organism’s DNA can be determined.

• The DNA base sequence of one organism can then be compared to the DNA base sequence of another organism, to see how closely related they are.

• Closely related species will have a higher percentage of similarity in base order

What is comparing amino acid sequence?

• The sequence of amino acids in a protein is coded for by the base sequence in DNA

• Related organisms have similar DNA sequences and so similar amino acid sequences in their proteins

• The more similar the amino acid sequence in two different species, the more closely related the species are

What are immunological comparisons?

• Similar proteins will bind to the same antibodies

• If the proteins in two species bind to the same antibodies, they are closely related

How was genetic diversity estimated earlier?

• Early estimates of genetic diversity were made by looking at the frequency of measurable or observable characteristics in a population.

• Since different alleles determine different characteristics, a wide variety of each characteristics in a population indicates a high number of different alleles- and so a high genetic diversity

How can we measure genetic diversity directly?

• Different alleles of the same gene will have slightly different DNA base sequences.

• Comparing the DNA base sequences of the same gene in different organisms in a population allows scientists to find out how many alleles of that gene there are in that population

• Different alleles will also produce slightly different mRNA base sequences, and may produce proteins with slightly different amino acid sequences, so these can also be compared