Investigating diversity

How can genetic diversity within or between species be measured?

● Comparing frequency of measurable or observable characteristics

● Comparing base sequence of DNA

● Comparing base sequence of mRNA

● Comparing amino acid sequence of a specific protein encoded by DNA and mRNA

Explain how comparing DNA, mRNA and amino acid sequences can indicate

relationships between organisms within a species and between species

● More differences in sequences → more distantly related / earlier common ancestor

● As mutations (change in DNA base sequences) build up over time

● More mutations cause more changes in amino acid sequences

Explain the change in methods of investigating genetic diversity over time

● Early estimates made by inferring DNA differences from measurable or observable characteristics

○ Many coded for by more than one gene → difficult to distinguish one from another

○ Many influenced by environment → differences due to environment not genes

● Gene technologies allowed this to be replaced by direct investigation of DNA sequences

Explain how data should be collected when investigating variation within a

species quantitatively

Explain how data should be processed and analysed when investigating

variation within a species quantitatively

Exam insight: common mistake ❌