Mendel and the gene

What phenotypic ratio of seed shape did Mendel observe in the F2 generation?

3:1 Dominant gene/recessive gene

Provide an example of blending inheritance.

A purple flower and a white flower would create a light purple flower

How did Mendel create hybrids of the P generation?

After self-pollination, he grew out pure line seeds of both varieties until they flowered. To control against unwanted pollination, the flowers were covered with mesh bags. Once fertile, pollen was collected with a sterilized paint brush from the flowers of one phenotype and used to pollinate the opposite phenotype

What is the expected phenotypic ratio of the cross between a homozygous purple flower (FF) and a homozygous white flower (ff): FF x ff ? What is the expected genotypic ratio?

All purple flowered plants, all heterozygotes

What is Mendel's Law of Segregation?

Alleles pairs separate during gamete formation, and reunite randomly at fertilization

was the widely accepted inheritance hypothesis Mendel was testing?

Blending Inheritance

In a pedigree analysis, what are the parental genotypes if one of their children express a different phenotype?

If two parents have the same phenotype and produce a child that has a different phenotype, the child's phenotype must be the recessive expression. Furthermore, the child's genotype must be homozygous recessive (i.e. aa), and the genotypes of both parents must be heterozygous (i.e. Aa).

Did the results of Mendel's dihybrid cross support dependent or independent assortment?

Independent

What were the predicted results supporting dependent assortment of a dihybrid cross?

It would not produce plants with a combination of dominant and recessive phenotypes from a dihybrid cross.

What was the prediction of the phenotypes for F1 generation based on the blending inheritance hypothesis?

Mendel expected to get an intermediate result of slightly wrinkly seeded plants from a cross of pure line smooth seeded plants with pure line wrinkly seeded plants.

What are the three principles of Mendel's Particulate Inheritance model?

Principle of Dominance - Dominant allele exhibits if present The Principle of Segregation - each gamete receives exactly one of the two alleles randomly. The Principle of Independent Assortment predicts alleles coding for different phenotypes are segregated independently from one another.

What are pure lines?

Something that produces known phenotypes

How did Mendel's results of the F1 generation conflict with the prediction of blending inheritance?

The hybrids were not semi-wrinkly. Rather, they were identical in shape to the round seeded pure lines.

What is Mendel's Principle of Dominance?

The principle of dominance states that some alleles are dominant and others are recessive

What was Mendel's conclusion from his results of the F1 generation based on seed shape?

The smooth seed phenotype masked the expression of the wrinkly seed phenotype.

What were the predicted results supporting independent assortment of a dihybrid cross?

all allele combinations were possible in gamete production. The prediction of the phenotypic ratio of independent assortment in this case would be 9 dominant/dominant: 3 dominant/recessive: 3 recessive/dominant: 1 recessive/recessive.

What is the hypothesis of independent assortment?

alleles for different phenotypes are sorted into gametes independently from one another. In other words, receiving an allele for one phenotype (e.g. flower color) does not determine the presence of another phenotype (e.g. seed color).

What type of experiment did Mendel use to test the dependent vs. independent assortment hypotheses?

dihybrid cross

What is the F1 generation?

hybrid offspring of the P generation, first filial generation

What is the F2 generation?

offspring of the F1 generation

What is the P generation?

parental generation

What is a phenotype?

physical appearance

What is the hypothesis of dependent assortment?

physical characteristics are linked during gamete formation. For example, an allele that codes for a specific flower color is connected to an allele for seed color.

How are pure lines created?

self-pollination