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Genetic Diversity

Biology: AQA A Level, topic 4.7.1

Investigating Genetic Diversity

Genetic diversity can be investigated both within species and between species in the following ways:

Comparing characteristics

Comparing characteristics

  • The frequency of measurable and visible characteristics can be compared between individuals.
  • E.g. The differences in height within an age group.
  • E.g. The differences in brain size between humans and chimpanzees.
  • It is important to note that generally comparing visible characteristics has been replaced by genetic techniques.
DNA base sequence

DNA base sequence

  • The sequences of bases in the DNA can be compared between individuals.
  • The greater the differences in base sequence between two individuals, the more distantly related the individuals.
  • E.g. An individual will have a DNA base sequence that is more similar to their father's than a random member of the population.
mRNA base sequence

mRNA base sequence

  • The sequences of bases in mRNA can be compared between individuals.
  • The greater the differences in base sequence between two individuals, the more distantly related the individuals.
Amino acid sequence

Amino acid sequence

  • The sequence of amino acids in proteins can be compared between individuals.
  • The greater the differences in amino acid sequence between two individuals, the more distantly related the individuals.
  • E.g. Cytochrome C is an electron carrier protein that forms a part of the electron transport chain in respiration. There is a 33% difference in the amino acid sequence between mammals and insects.

Gene Technologies

Gene technologies are used to investigate genetic diversity by studying the genome. Gene technologies are a recent development that have dramatically changed the way genetic diversity can be studied.

Visible characteristics

Visible characteristics

  • Before gene technologies were invented, genetic diversity could be inferred by comparing visible characteristics between organisms.
  • The frequency of characteristics in a population was used as an indirect measure of diversity.
  • E.g. The number of different coat colours of horses and the number of individuals of horses with each coat colour would indicate genetic diversity.
Gene technologies

Gene technologies

  • Gene technologies allow the alleles in an individual to be directly measured.
  • Alleles are the different versions of a gene and alleles are what gives rise to genetic diversity in a population.
  • Gene technologies allow genetic diversity to be directly measured.
  • E.g. The number of different alleles for a single gene and the number of individuals with each allele directly shows genetic diversity.

Test yourself on Genetic Diversity

  • How can genetic diversity between and within species be investigated?

  • Which of these statements about investigating genetic diversity are true?

  • What is the percentage difference in the amino acid sequence for cytochrome C between mammals and insects?

  • Which of the following statements about gene technologies are true?

  • What feature of the genome is measured when measuring genetic diversity?

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