Variation and the human genome project

Question 1

What are the two causes of variation

within a species?

Answer 1

● Genetics

● Environment

Question 2

What is genetic variation?

Answer 2

● Variations in the genotypes of organisms of
the same species due to the presence of
different alleles
● Creates differences in phenotypes

Question 3

What creates genetic variation in a

species?

Answer 3

● Spontaneous mutations

● Sexual reproduction

Question 4

What is a mutation?

Answer 4

Arandom change to the base sequence

in DNA which results in genetic variants

Question 5

State the three types of gene mutation

Answer 5

● Insertion
● Deletion
● Substitution

Question 6

How may a gene mutation affect an

organism’s phenotype?

Answer 6

● Neutral mutation does not change the sequence of amino acids.
Protein structure and function same. No effect on phenotype.
● Mutation may cause a minor change in an organism’s phenotype e.g.
change in eye colour.
● Mutation may completely change the sequence of amino acids. This
may result in a non-functional protein. Severe changes to phenotype.

Question 7

What is environmental variation?

Answer 7

● Variations in phenotype that are acquired
during the lifespan of an organism
● Due to environmental factors e.g. diet,
lifestyle, climate, exposure to light etc.

Question 8

What is the Human Genome Project?

Answer 8

● Scientific research project involving thousands of
scientists across the globe which successfully mapped the
entire human genome
● Scientists now aim to identify the function of every gene in
the human genome

Question 9

How can the results of the Human Genome Project

be applied to medicine?

Answer 9

● Enables scientists to understand how lifestyle factors interact with genes -
identifying predisposition to disease and possible preventions
● Disease-causing alleles identified more rapidly and the appropriate
treatments prescribed earlier on
● Scientists can predict an individual’s response to certain drugs. New drugs
can be developed which are tailored to a specific allele.

Question 10

What are drawbacks associated with the
discoveries of the Human Genome
Project?

Answer 10

● Knowledge of predisposition to a disease can be stressful
● Societal pressure influencing the decision to have children
● Discrimination by employers, insurance firms etc.