Question

You should explain your chosen DNA typing method and try to persuade scientists in the field that it’s the superior option. Your pamphlet should describe the process involved with your chosen type, and the benefits of it, in terms of the accuracy of the results of the test and the usefulness of it in forensic science. Your information can come from the module but should be supplemented with additional online research. Provide details about how the DNA and cells are used—keep your audience in mind!

Answer 1

The typing method chosen is that of microsatellites.

Every living being has the privilege of being unique, distinct from its congeners. It is the expression of the information coded by its genome: the long DNA molecule contained in the nucleus of each of its cells. It is on this principle that the identification of an individual and its direct application rests, the control of filiation.

On the long DNA molecule, hereditary support, there are regions that encode proteins: genes and other non-coding regions. In the latter, there are regions called microsatellites which consist of repetitions of sequences of 2, 3 or 4 nucleotides. The number of microsatellites in the genome is estimated to be between 50,000 and 100,000. The most frequently used in equines are 2-nucleotide repeats.

For a given microsatellite:

* There are different alleles defined by the number of these repetitions, variable from one individual to another (eg: 6 repetitions will define the A allele, 8 repetitions will define the B allele, ...).

* This number is stable during the life of the animal and is transmitted to his offspring.

In each individual, a microsatellite has two alleles (variants): one of paternal origin, the other of maternal origin. When both alleles are identical, the individual is described as homozygous; when they are different, he is heterozygous.

All the alleles of a microsatellite constitute genetic polymorphism. The higher the number of alleles, the more effective the microsatellite will be in identifying an animal and distinguishing it from others. The typing of all the microsatellites studied defines the genotype of the individual.

The methods of studying microsatellites are reproducible, automatable and very precise, therefore reliable and effective. The molecular biology techniques used make it possible to carry out the steps necessary for the analysis.

1st step: DNA extraction

2nd step: amplification of DNA microsatellites

3rd step: separation of the different alleles by electrophoresis

4th step: Result of genotype analysis and interpretation.