Quiz Genetics Basics

Introduction to Genetic Testing

The following questions are based on information provided in the ‘Introduction to Genetic Testing’ webinar. For each question select the correct answer. There is only one correct answer for each question.

1. DNA is our hereditary material, it is the carrier of our genetic information passed from parent to offspring. Which statement is true?

All of our DNA is located in the cell nucleus (nDNA) within our chromosomes

DNA is a single stranded helix.

DNA is a double stranded helix joined together by complimentary base pairs i.e. adenine (A) and Thymine (T), guanine (G) and cytosine (C).

Two DNA base pairs join to make a unit. Adenine (A) pairs with cytosine (C) and thymine (T) pairs with guanine (G).

All of the above.

2. True or false? A nucleotide is made up of one base + one sugar + phosphate. Nucleotides join together (base pairs) and are arranged in two long strands that form a spiral called a double helix.

True

False

3. Which statement is true with regard to genes?

Genes are made up of DNA, they are a template to make proteins.

Genes are base pairs in varying sequences and the basic physical and functional unit of hereditary.

All genes together make up the human genome.

Genes are located on chromosomes. Humans have 46 chromosomes (23 pairs). Within the pairs of chromosomes, we have 2 copies of each gene.

All of the above.

4. Which statement is true with regard to genetic mutations?

A genetic mutation is a change in the genomic sequence of an organism. This change has no effect on the characteristics of an organism.

A genetic mutation is high penetrance (cause-effect relationship), conveying a high probability that the effect will be expressed and ‘visible’.

A genetic mutation only affects a single base pair or gene. It cannot affect the whole chromosome or large parts of the chromosome.

A genetic mutation needs a dietary or lifestyle intervention to be expressed.

All of the above.

5. Which of the following statement is false with regard to genetic variations.

These usually refer to traits that are affected by the environment e.g. nutrition and exercise, whereby the gene interacts with the environment to influence disease risk.

They are low penetrance.

They are minor impact and do not cause disease on their own, but rather convey susceptibility to disease.

They are usually single nucleotide polymorphisms or a small sequence of nucleotides.

Sickle cell anaemia is a good example of a low penetrance genetic variation.

6. What is a single nucleotide polymorphism (SNP)?

It is a gene variant caused by a change in a single nucleotide or base, occurring on average once in every 300 nucleotides. It can act as a biological marker, indicating a predisposition towards a behaviour, physical or physiological attribute.

It is a gene mutation, where one nucleotide is replaced with another and causes a disease or syndrome.

It refers to a single base, within a base pair.

7. Refer to your SNP guide and specifically the SNP PON1 192 Gln>Arg (A>G). Which statement is false with regard to this SNP?

PON1 is the gene name; 192Gln>Arg indicates that at position 192 on the PON1 gene, there may be an A allele or G allele; the change from A to G causes a change in the amino acid from glutamine to arginine.

A person may carry one of three genotypes of this SNP; AG which is the heterozygous genotype and AA and GG which are the homozygous genotypes.

The outcome of this SNP (phenotype), is that individuals carrying the G allele have lower concentrations of PON1 and decreased PON1 activity, which has been linked to increased risk for atherosclerosis, ischemic stroke, metabolic syndrome and certain cancers.

The environmental interaction is that the Mediterranean Diet has been associated with increased PON1 activity and a decreased risk of atherosclerosis.

Individuals carrying the AA genotype are advised to increase their intake of mono-unsaturated fats, fresh fruit and vegetables and increase exercise, in order to reduce their risk of cardiovascular disease and improve their HDL cholesterol levels.

8. Based on your understanding of complimentary alleles, when considering the SNP PON1 192 A>G, depending on what strand you are looking at this may also be referred to in the literature as PON1 192 T>C

True

False

9. A phenotype is genetic make-up of a cell, organism or individual, usually with reference to specific characteristics whereas a genotype is the composite of an organisms’ observable traits such as behaviour, development and physiological properties.

True

False

10. Which of the following are not inclusion criteria for a SNP to be included in the DNAlysis reports?

There is significant evidence linking the gene to a phenotypic outcome.

The SNP within the gene exerts direct influence over specific biochemical processes that create know symptoms or disease.

The SNP must be modifiable by environmental factors such as diets, nutrients, exercise and lifestyle and must consider nutrients that are readily available.

The SNP is common and relevant to the population.

The impact of the SNP and clinical interventions are measurable.

All effects of a specific nutrient intake with certain genetic variants are positive. No negative effects are examined.

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Introduction to Genetic Testing