Why look at G+C content?

Andrew Mitchell moths at Glue.umd.edu
Thu Mar 7 09:56:08 EST 1996


As we are all aware, base composition biases can seriously affect 
phylogenetic analyses of DNA sequence data.   I have seen many papers in 
which such biases are assessed by examining the G+C content of 
sequences.  If this value is approximately 50% then authors conclude 
there is no base composition bias.  However, that 50% G+C could break 
down further into 45% G, 5% C, 10% A and 40% T - extreme composition 
bias.  So why the fixation with G+C content?  Is it simply a hangover 
from the days before DNA sequencing, or did I miss something?

Andrew Mitchell




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