4B - DNA technology, classification and diversity Flashcards
What can clarify evolutionary relationships?
Advances in techniques.
What 3 advances in technologies have been used to help update classification systems?
Genome sequencing.
Comparing amino acid sequence.
Immunological comparisons.
How has genome sequencing led to updates in the classification system?
The entire base sequence on an organism’s DNA can be determined so they can be compared to other organism’s base sequence to see how closely related they are.
Closely related species will have a higher percentage of similarity in their DNA base order.
How has comparing amino acid sequences led to updates in the classification system?
Proteins are made of amino acids and the sequence of amino acids in a protein is coded for by the base sequence in their DNA. Related organisms have similar DNA sequences and so similar amino acid sequences in their proteins.
The more similar the amino acid sequence in different species, the more closely related they are likely to be.
How have immunological comparisons led to updates in the classification system?
Similar proteins will also bind to/with the same antibodies.
What have gene technologies done for genetic diversity?
Changed the way genetic diversity is assessed.
What is genetic diversity?
The number of different alleles in a population.
How have gene technologies changed the way genetic diversity is assessed?
It used to be assessed by looking at the frequency of observable characteristics in a population.
Since different alleles determine different characteristics a wide variety of each characteristic in a population indicates a high number of different alleles and so a high genetic diversity.
However, gene technologies have now been developed that allow us to measure genetic diversity directly which give more accurate estimates of the genetic diversity within a population or species and allow them to be compared between species.
How do gene technologies allow us to measure genetic diversity more directly?
For example,
Different alleles of the ame gene will have slightly different DNA base sequence. 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.
Why can observable characteristics be used as a measure of genetic diversity?
Since different alleles determine different characteristics a wide variety of each characteristic in a population indicates a high number of different alleles and so a high genetic diversity.
What are ways to compare genetic diversity?
Compare observable characteristics.
Compare DNA base sequences.
Compare the base sequence of mRNA.
Compare the amino acid sequences of proteins.
