Analysis of immunoglobulin genes from germinal centre B
cells after repeated antigen exposure shows extensive mutation within the
variable region. While many mutations are silent, amino acid–altering changes
are disproportionately found in regions that directly contact antigen.

Which explanation best accounts for this
non-random distribution of mutations within antibody genes?

Question

Analysis of immunoglobulin genes from germinal centre B
cells after repeated antigen exposure shows extensive mutation within the
variable region. While many mutations are silent, amino acid–altering changes
are disproportionately found in regions that directly contact antigen.

Which explanation best accounts for this
non-random distribution of mutations within antibody genes?

Answer

All
mutations affecting antigen binding are eliminated

Answer

Positive
selection favours amino acid changes in regions that influence antigen binding

Answer

The
mutation machinery avoids framework regions entirely

Answer

Mutations
are randomly distributed but undetected outside contact sites

Crowdly

Analysis of immunoglobulin genes from germinal centre B cells after repeated an...

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