The similarity of amino-acid sequences in some proteins will reflect how closely two species are related.Comparisons can be done by counting the number of similarities or by counting the number of differences.An example is the sequence of haemoglobin in primates.Immunological comparisons of proteins can be done by injecting a protein from one species into another animal, such as a rabbit, which makes antibodies against it. Serum containing these antibodies is then mixed with the same protein from other species. The more precipitate that forms, the more similar the proteins and the more closely related the species.
Comparing Amino-acids Sequences
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Specification: AQA Biology (7401), AS-level, 3.4.7 Investigating diversity. Topic: Biodiversity.
Key terms in this lesson
- antigen
- A protein or glycoprotein, usually on a cell surface, that is recognised as foreign by the immune system and triggers an immune response.
- haemoglobin
- A globular, quaternary protein in red blood cells, made of four polypeptide chains each with a haem group, that binds and transports oxygen.
- species
- A group of organisms with similar characteristics that can interbreed to produce fertile offspring.
More in Biodiversity
- Managing Ecosystems
- Investigating Diversity
- Comparing DNA
- Comparing mRNA
- Sampling
- Random Sampling
- Normal Distribution
- Mean, median and Mode
All 33 lessons in Biodiversity · All AQA AS-level Biology topics