Introduction to Evolutionary Conservation

Mutations occur spontaneously in each generation, randomly changing the amino acid sequences of proteins. Individuals with mutations that impair critical functions of proteins may have resulting problems that make them less able to reproduce. Harmful mutations are lost from the gene pool because the individuals carrying them reproduce less effectively. Over time, only harmless (or very rare beneficial) mutations are maintained in the gene pool. This is evolution.

Examples

Consider the protein methyl CpG binding protein 2 (MeCP2). Although its function is still unclear, it is expressed throughout the body, and disruption of its function causes problems with brain development and function. Some mutations in MeCP2 cause Rett Syndrome, a severely debilitating condition affecting mostly women.

V. Introduction to Multiple Sequence Alignment (MSA) and Conservation     ConSurf Server     Structure of Atomic Coordinate ("PDB") Files

21. <a href="https://www.proteopedia.org/wiki/index.php/Conservation%2C_Evolutionary" target="_blank">Evolutionary conservation</a> identifies functional sites in protein molecules.
    

    Effect of mutation on protein function	Genetic consequence	Example
    Function LOST**	CONSERVED: mutation LOST from gene pool	R133C*
    None	NOT conserved: mutation remains in gene pool	E143?*
    in methyl CpG binding protein 2 (MeCP2), <a href="https://www.proteopedia.org/wiki/index.php/3c2i" target="_blank">3c2i</a>:    ASASPKQRRS IIRDRGPMYD DPTLPEGWTR KLKQRKSGRS AGKYDVYLIN    PQGKAFRSKV ELIMYFEKVG DTSLDPNDFD FTVTGRGSPS RHHHHHH          ^          ^ R133C causes <a href="slides/rett/rett.htm" target="_blank">Rett syndrome,</a> a severe neurological disorder. Gray: disordered in crystal, absent in model 3c2i.

    Notes and References

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