mutations and recombination

Question 1

An allele that produces a gene product having a new activity is known as
(-morph)

Example?

Answer 1

as it has a new function, it is a neomorphic allele

Question 2

Apert syndrome in humans is caused by a missense mutation in the FGF2R (FGF receptor 2) gene.
The mutant protein has increased signalling activity compared to the wild type protein. This allele is known as (-morph)

Answer 2

it has an increase in activity so it is a hypermorphic allele

Question 3

The Drosophila tinman gene is essential for heart formation. Loss of function alleles of this gene are fully recessive.
Homozygotes for a hypomorphic allele of tinman have abnormal, partially formed, hearts. Heterozygotes for the amorphic and wild type alleles (i.e. amorph/wild type) will have:
A no heart C abnormal E very abnormal
B normal heart D slightly abnormal

Answer 3

so as a LOF (bascially a a-morph) is recessive, a heterozygote only has one bad copy so would have a normal heart still!

Question 4

what is the Ames test? describe how it works

Answer 4

simple test that uses bacteria to assess the mutagenic capacity of a chemical

uses a mutated strain of Salmonella typhimurium which can’t make histidine which is necrsay for cell survival . So if we grow it in culture without histidine it cant grow
if the chemical is highly mutagenic, it can revert this mutation

Question 5

in the Ames test, if there are lots of colonies that have grown on the agar, what does that indicate about the mutagenic capacity of that chemical?

Answer 5

if lots of colonies have grown, this chemical is highly mutagenic as the mutation of the bacteria has reverted as a result of exposure to that chemical/mutagen