The document summarizes several types of monohybrid crosses including simple dominance, sex-linked inheritance, codominance, and incomplete dominance. For each cross, it provides the genotypic and phenotypic ratios and frequencies for traits such as eye color, organism size, skin color, tail color, and number of toes. The crosses demonstrate basic Mendelian genetics patterns including dominance, recessiveness, sex-linkage, codominance, and blending inheritance.

1. Monohybrid Crosses
By: Kimberly Escobar 3rd period.

2. Simple Dominance: Color of Eye
(R= Red, r= black)
RR Rr
RR RrR
R
R r
Genotypic Ratio: 2:2 (RR:Rr)
Genotypic Frequency: 50% RR, 50% Rr
Phenotypic Ratio: 4 (Red)
Phenotypic Frequency: 100% or 1 (Red)

3. Simple Dominance: Size of the Organism
(B= Big, b= small)
Bb bb
Bb bb
b
b
B b
Genotypic Ratio: 2:2 (Bb:bb)
Genotypic Frequency: 50% or 1/2 Bb, 50% or 1/2 bb
Phenotypic Ratio: 2:2 (Big:Small)
Phenotypic Frequency: 50% or 1/2 Big, 50% or 1/2 Small

4. Sex-Linked: Skin Color
( G= Gold, g= silver)
XGXG XGXg
XGY XgY
XG Xg
XG
Y
Genotypic Ratio: 1:1:1:1 (XGXG:XGXg:XGy:Xgy)
Genotypic Frequency: 25% or 1/4 XGXG , 25% or 1/4 XGXg , 25% or 1/4 XGy, 25% or 1/4 Xgy.
Phenotypic Ratio: 3:1 (Gold:Silver)
Phenotypic Frequency: 75% or 3/4 gold, 25% 1/4 silver

5. Codominance: Tail Color
(TT=Red, TT’= Red & Yellow, T’T’= Yellow)
TT TT’
TT’ T’T’
T
T’
T’
T
Genotypic Ratio: 1:2:1 (TT:TT’:T’T’)
Genotypic Frequency: 25% or 1/4 TT, 50% or 1/2 TT’, 25% or 1/4 T’T’
Phenotypic Ratio: 1:2:1 (Red:Red & Yellow:Yellow)
Phenotypic Frequency: 25% or 1/4 Red, 50% or 1/2 Red & Yellow, 25% or 1/4 Yellow

6. Incomplete: Number of Toes
(CC=5 toes, cc= 7 toes, Cc=6 toes)
CC Cc
Cc cc
C c
C
c
Genotypic ratio: 1:2:1 (CC:Cc:cc)
Genotypic Frequency: 25% or 1/4 CC, 50% or 1/2 Cc, 25% or 1/4 cc
Phenotypic Ratio: 1:2:1 (5 toes:6 toes:7 toes)
Phenotypic Frequency: 25% or 1/4 5 toes, 50% or 1/2 6 toes, 25% or 1/4 7 toes