PBG/MCB621
Computer exercise 10/26/2012
The “Oregon Wolfe Barley” population is a Doubled Haploid (DH) population developed from the cross
between two genetic stocks: OWB-D and OWB-R.
OWB-D has dominant alleles for most of the phenotypic traits whereas OWB-R has recessive alleles. The
population is highly polymorphic and it has been a very important resource for research and education.
For the exercise, we will analyze 4 loci in this population:
-Locus 1: is a STS-Marker to detect whether starch is waxy or non waxy
-Locus 2: is a STS-Marker of unknown position and function
-Locus 3: is SNP marker located on the gene coding for the protein GDP-mannose 3,5-epimerase
-Locus 4: is a visual marker for row type (2-row infloresc4ence or 6-row inflorescence)
1) Calculate first whether each locus is segregating according to the 1:1 ratio expected in a DH
population
X2 value
Probability
Segregating 1:1
(Y/N)
Probability
Linked (Y/N)
Locus 1
Locus 2
Locus 3
Locus 4
2) Calculate second whether the loci are linked or not
G value
Locus 1 and Locus 2
Locus 1 and Locus 3
Locus 1 and Locus 4
Locus 2 and Locus 3
Locus 2 and Locus 4
Locus 3 and Locus 4
3) Calculate the recombination frequency for each pair of linked loci
Rec. Freq.
r23
r24
r34
4) What is the most likely order of the three linked loci?