Tall/short Flashcards
Candidate gene?
A good guess
What is the enzyme responsible for GA20>GA1————-would be different in tall and short peas.
Gibberellin 3B hydroxylase
____is what differs between tall and short pea plants not hot enumber of internodes
internode length
How does one find out which clone has the sequence of interest?
In this study by Diane Lester they used a phage library, the cDNA’s are instered into the phage(virus) genomes. This phage solution is added into bacteria, these bacteria die. Then you find the bacteria that have died from phage containing GA 3b Hydroxylase by probing
Once you have the sequence of Le and le plants you can compare by using PCR to obtain the GA b3 cDNA sequence from le. WHat are the differences?
A difference in one amino acid Alaine in Le and threonine in le.
But they could not be sure that GA 3B is responsible.
Next they did a southern blot.
-digested genomic DNA from two plants which is then proved by cDNA
When one cDNA probe labels two genomic fragments(making two bands) this means what?
The restriction enzyme cuts ontop of the probe creating both sides of the probe to light i up
WHen using the southern blot it is found that which enzyme is varying at Le and le.
Hindlll
Regarding the Hindlll data, what does the different sized band mean?
One strain has a cut site that the other does not
pg 19 lecture 3…. what does this photo mean
Every le/ short plant is homozygous for the cut site and the tall plants are hetero or homozygous for the non cut.
This tells use tat there is a cut site beside the le gene that is not present in the Le allele. This is consistent with the hypothesis that the GA 3b Hydroxylase gene is different in all surveyed tall and short plants.
The restriction enzyme ‘map’ shows that the extra le cut site is not in a coding zone so it shouldn’t effect the GA 3B Hydro leading to short peas. So what is it?
It is an association with the phenotype that is due to linkage
What is the difference between these two GA 3b Hydri gene alleles at the DNA level that leads to the phenotypic difference, that is, to the reduced levels of the GA 3B Hydro activity that leads to less G20>G1 that ultimate leads to shorter internode lengths.
the conversion of GA2o to GA1 is not present in short peas
this is because of the AA sub
