Kussemek said:
I am looking at my notes from TPR, attempt 1 and am using Audio Osmosis for attempt 2 in addition to TPR class. TPR really only emphasized 3 types of mutations (i guess you could call them 2)...those being point mutations and insertion and deletion. AudioOsmosis mentions netural, transposition, back mutation, wildtype... What are the basics we need to know about mutations? Thank you.
Hi!
Good information given above.
According to the AAMC MCAT student manual, the following is fair game for mutation material: "random, translation error, transcription error, base substitution, inversion, addition, deletion, translocation, mispairing."
Here are my quick thoughts (skipping insertion and deletion and point mutations since you said you had those):
Wild-type mutations: a base substitution that does not result in a change of amino acid, usually no effect on phenotype (apparently some really subtle things can occur but I wouldnt worry about it for MCAT level questions). This one is confusing because here the "wild-type" refers only to the phenotype, not to both the phenotype and the genotype as I usually hear the term used.
Neutral mutations: have no effect on function.
Back mutations: When something was once A but is now B changes back to A again.
Inversion mutations: when a sequence of nucleotides is reversed (DNA level), or when a sequence of genes is reversed (chromosome level).
Transposition mutations: jumping genes (transposons) which can cause translocation, insertion, and deletion mutations.
Translocation mutations: genes from one of a pair of homologous chromosomes separate and attach to the other chromosome in the pair. Can occur during crossing over.
Obviously, errors can occur in translation (wrong AA) and transcription (wrong base) both.
Good illustrations available at:
http://www.biology-online.org/2/8_mutations.htm
http://www.people.virginia.edu/~rjh9u/chrominv.html
Nice, concise reference about transposition (but way more than necessary information):
http://wiki.cotch.net/index.php/Transposition
I hope that was helpful!