8B Dihybrid Crosses

Question 1

What are dihybrid crosses?

Answer 1

Dihybrid crosses are when we want to predict the genetic outcomes of two traits, and calculate the likelihood of different combinations of genes being expressed in offspring

Question 2

What are the steps to completing an unlinked dihybrid cross?

Answer 2

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Question 3

What are the steps to completing a linked dihybrid cross?

Answer 3

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Question 4

What is the ratio of phenotypes created by two heterozygous individuals?

Answer 4

9:3:3:1

Question 5

What are linked genes?

Answer 5

Genes that are close together on the same chromosome and are likely to be inherited together.

Question 6

What is a map unit?

Answer 6

A map unit is a measure of distance between two genes. 1 map unit is a 1% chance of crossing over occurring.

Question 7

What is a recombinant chromosome?

Answer 7

A chromosome which is not identical to one of the homologous chromosomes in a diploid cell.

Question 8

What is a parental chromosome?

Answer 8

A chromosome which contains the same combination of alleles as one of the parents’ chromosomes.

Question 9

How do you write the genotype of linked genes?

Answer 9

You write the alleles on one chromosome first, then add a forward slash (/), then write the alleles on the second chromosome. Eg. Be/be

Question 10

Have a go at some examples to practice completing dihybrid crosses????

Answer 10

Have a go at some examples to practice completing dihybrid crosses????