1
Biol 322 11/17/09 lecture
See announcement on 322 web site
Issues with aha3 assignment:
1. double mutant does not mean homozygous for the
mutant allele:
• Homozyous for mutant allele: bb
• Double mutant: organism shows two different
mutant phenotypes
2. Prediction of 1:2:1 genotype or 1:2 or 2:1 genotype
frequencies with no indication of the order of
genotype listing:
• Assuming no complications to the segregation of a
single gene trait with 2 alleles, the genotype
distribution should be 1:2:1 homozygous wild-
type: heterozyous: homozyous for the mutant allele
• Assuming no complications to the segregation of a
single gene trait with 2 alleles, the genotype
distribution should be 1:2:1 +/+: +/-: -/- where +
= wild-type allele and - = recessive allele
3. Needed to indicate that the gametophyte was the
haploid pollen or ovule stage – 1:1 ration results from
inviability of the pollen or the ovule carrying the
mutant allele
4. Carelessness in analyzing the meaning of p value
and how to use it
