I will use a simple example of Height......
T (tall) is dominant over t (short). So we have 2 ways to make a tall offspring: TT and Tt
't' is a recessive trait so it will take two 't's together to make a short offspring: tt
Homozygous dominant means it has 2 of the same allele, and that this allele is the dominant one. So T T
Heterozygous means it has 2 different alleles. So T t
A monohybrid cross simply means "find out how this gene is inherited by the offspring".
To answer the question we put the parents (TT and Tt) in a punnet square...
.....T.......T
T....TT...TT
t.....Tt....Tt
The phenotype (how they actually look) is tall for all 4 of them.
TT is tall and Tt is also tall (even though they have a short 't' allele, the tall 'T' allele is dominant, making them tall anyway.
Therefore the ratio of tall to short is 4:0 which can be reduced to 1:0
The expected phenotypic ratio will be 100% dominant. This is so because if we take AA to be the homozygous individual and Aa to be the heterozygous, the Punnett square will give us the offspring AA, AA, Aa, and Aa. They will all have one dominant allele, resulting in a dominant phenotype.
The expected genotype ratio from a heterozygous x heterozygous cross is 1:2:1.
For example, in the cross Bb x Bb the genotype ration would be 1BB:2Bb:1bb
i believe it would be AA AA Aa Aa or all dominate traits showing, two homozygous dominate, two heterozygous dominate. I'm in college bio, but its been a lilwhile since we studdied this.
Crossing Aa with Aa would get you AA, Aa, Aa and aa. Two heterozygotes and two homozygotes. Of the latter, one dominant and one recessive.
A homozygous dominant cross?
AA X AA
Yields all AA
========
the ratios would be 9:3:3:1
1:1
1:0
1 homozygous dominant: 2 heterozygous: 1 homozygous recessive
In the P generation, one parent is homozygous dominant and the other parent is homozygous recessive. In the F1 generation, the product of a cross between the P generation, the offspring are all heterozygous. In the F2 generation, the product of a cross between the F1 generation, the expected result is 1/4 homozygous dominant, 1/2 heterozygous, and 1/4 homozygous recessive.
Expected phenotypic ratios are always the same: 3:1. Expected genotypic ratios are always the same: 1:2:1.
If two homozygous plants with contrasting traits are crossed, the expected genotypes for the offspring will be heterozygous. The dominant trait would be expressed, but they'd be carriers for the recessive trait.
Make a Punnet Square:White HETEROZYGOUS---WwRed HOMOZYGOUS--ww (this one is recessive because the white characteristic dominated in the heterozygous type)So:W ww Ww www Ww wwThese four are the potential types of the offspring, they will either be HETEROZYGOUS WHITE or HOMOZYGOUS RED, no homozygous white
50%
1 homozygous dominant: 2 heterozygous: 1 homozygous recessive
The phenotypic ratio of 2 hybrids would be 3:1 while the genotypic would be 1:2:1. ChaCha on!
In a monohybrid cross with one parent homozygous dominant and the other homozygous recessive The phenotype of the F1 offspring will be 100% that of the parent with the dominant allele. A cross of two of the F1 offspring will be 75% phenotypically like the dominant allele and 25% will be hommozygous recessive or 3 to 1
Rr
The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be 9:3:3:1. This ratio is obtained when two heterozygous individuals are crossed for two traits that are independently inherited. The ratio represents the different combinations of phenotypes that can arise from the cross.
In the P generation, one parent is homozygous dominant and the other parent is homozygous recessive. In the F1 generation, the product of a cross between the P generation, the offspring are all heterozygous. In the F2 generation, the product of a cross between the F1 generation, the expected result is 1/4 homozygous dominant, 1/2 heterozygous, and 1/4 homozygous recessive.
In the P generation, one parent is homozygous dominant and the other parent is homozygous recessive. In the F1 generation, the product of a cross between the P generation, the offspring are all heterozygous. In the F2 generation, the product of a cross between the F1 generation, the expected result is 1/4 homozygous dominant, 1/2 heterozygous, and 1/4 homozygous recessive.
Expected phenotypic ratios are always the same: 3:1. Expected genotypic ratios are always the same: 1:2:1.
If one trait is dominant over the other, then the resulting F1 generation would be expected to have the heterozygous genotype and dominant phenotype.
Because in heterozygotes, both alleles are transcribed and translated.
If two homozygous plants with contrasting traits are crossed, the expected genotypes for the offspring will be heterozygous. The dominant trait would be expressed, but they'd be carriers for the recessive trait.