Dihybrid Cross

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What is a dihybrid cross?

A cross between two homozygous parents who differ in two characteristics ie two genes are being studied in the same breeding experiment
In the dihybrid cross, the offspring with the same phenotype of the original parents are called...?

parentals
In the dihybrid cross, the offspring with different combinations of the parental phenotype are called...?

recombinants
What is a dihybrid backcross (testcross)?

It involves crossing the heterozygous hybrid with a double recessive. It allows us to test whether genes are linked or unlinked
When genes are on the same chromosome and their alleles are transmitted together, they are said to be...?

linked
What is the phenotypic ratio of the F₂generation from an unlinked F₁x F₁cross?

9 : 3 : 3 : 1
What is the phenotypic ratio of the F2 generation from an unlinked F₁backcross?

1 : 1 : 1 : 1
What is the phenotypic ratio of the F2 generation from a linked F₁ cross?

3 : 1
What is the phenotypic ratio of the F2 generation from a linked F₁backcross?

1 : 1
If two genes are completely linked then a backcross would not produce any F₂recombinants. However, when backcrosses are carried out the F₂ may be found to contain some recombinants. How can this be explained?

Crossing over
The seperation of linked genes and the new combinations of alleles is an important source of...?

variation
Where can chiasmata occur?

At any point along a chromosome
More crossing over can occur between two genes that are _______ ________ from each other than two that are ________ _______?
- farther away
- close together
What is the percentage number of the F₂recombinants called?

Recombination frequency (RF) or Cross-over Value (COV)
The higher the RF or COV the _______ ________ the genes are on the chromosome?

further apart
What can be used to map genes?

COV

Author

Anonymous

129951

Card Set

Dihybrid Cross

Description

Higher Biology - Unit Two - Dihybrid Cross

Updated

2012-01-23T16:36:53Z

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