Variation and inheritance

1

Which of the following human characteristics shows discrete variation?

2

What term describes a body characteristic that is controlled by more than one gene?

3

What form of variation do polygenic characteristics show?

4

What term can be used to describe a person’s eye colour or a fruit fly’s wing length?

5

Which of the following genotypes represents a heterozygous organism?

6

What name is given to different forms of the same gene?

7

If a person inherits a dominant allele from one parent and a recessive allele from their other parent, which phenotype will they show?

8

The pedigree chart below shows the inheritance of the genetic condition Huntington's. Individuals affected by the condition are represented by blue shapes. All other individuals are unaffected.

A pedigree chart which illustrates Huntington's disease with numbers 1 to 6.  number one: a male with normal cells has children with number 2 a female with affected cells. they have two children.  Number 4: a female with affected cells. Number 5: a male with affected cells. Female number 4 has a child with Number 3, a male with affected cells.  Their child, number six is a male with normal cells.

The allele (H) that causes the condition is dominant to the allele that leaves an individual unaffected. What are the genotypes of individuals 3 and 4?

9

The pedigree chart below shows the inheritance of the genetic disease Huntington's. Individuals affected by the condition are represented by shaded in shapes. All other individuals are unaffected.

A pedigree chart which illustrates Huntington's disease with numbers 1 to 6.  number one: a male with normal cells has children with number 2 a female with affected cells. they have two children.  Number 4: a female with affected cells. Number 5: a male with affected cells. Female number 4 has a child with Number 3, a male with affected cells.  Their child, number six is a male with normal cells.

The allele (H) that causes the condition is dominant to the allele that leaves an individual unaffected. The genotype of individual 2 is Hh. What is the expected ratio of phenotypes in the offspring of individuals 1 and 2?

10

In a monohybrid cross what symbol is used to illustrate the first generation of offspring?