Table 1: Complete all ten scenarios and record your results in Table 1. Always record the most dominant characteristic first, followed by the recessive. When you record phenotypic ratios for a monohybrid cross, there are only two possible phenotypes - either the dominant phenotype or the recessive phenotype. So you do not need to indicate the phenotype, simply put the dominant # first, followed by the recessive #.
Scenario # Genotype of
Parent I Genotype of
Parent II Genotypic Ratio
of Offspring Phenotypic Ratio
of Offspring
1
Gg gg
2
Gg Gg
3
LL ll
4
LL Ll
5
Ll Ll
6
Gg GG
7
Ll ll
8
GG gg
9
ll ll
10
gg gg
Genotype describes which genes (dominant or recessive) an organism has for a particular trait.
So, for Scenario 1 when you cross Gg x gg the possible genotype outcomes are Gg, Gg, gg, gg. The genotypic ratio is 2Gg:2gg.
Phenotype is how something looks.
The possible phenotypes for body color are the dominant trait gray (GG or Gg) or the recessive trait black (gg). So, you count up the number of dominant traits and the number of recessive traits and present them as a ratio.
In this case there are 2 dominant (Gg and Gg) and 2 recessive (gg and gg).
The phenotypic ratio would then be 2:2.
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