Genetic Variation

Question 1

What is the definition of a gene?

Answer 1

A gene is a region of DNA that contains all of the information required to produce a functional protein or RNA.

Question 2

What is the definition of a gene locus?

Answer 2

A gene locus is the unique position of a gene on the chromosome. Each individual’s genome contains the same genes in the same order i.e. at the same loci.

Question 3

What is the definition of a genotype?

Answer 3

The genetic constitution of either a genome or an individual locus. The genotype is distinct from its expressed features or phenotype.

Question 4

What is the definition of a genome?

Answer 4

Genome refers to all the genetic material (DNA) of an organism.

Question 5

What is the definition of a phenotype?

Answer 5

The expressed features of the genome and results from the interaction between the genotype and the environment.

Question 6

What is the definition of genetics?

Answer 6

The study of single genes and their effects.

Question 7

What is the definition of genomics?

Answer 7

The study of all the genes in the genome, how they interact and including their interactions with environmental factors.

Question 8

What is the definition of epigenetics?

Answer 8

Epigenetics the study of reversible, heritable mechanisms that influence gene expression without changing the DNA sequence.

Question 9

What is the definition of a wildtype?

Answer 9

The wildtype is the most common form of the gene within a population.

Question 10

What is the definition of a allele?

Answer 10

An allele is an alternative form of a gene which has one or more differences in its nucleotide sequence.

Question 11

What is the definition of homozygous ?

Answer 11

When the copies of the gene (alleles) present on each of a pair of homologous chromosomes are identical.

Question 12

What is the definition of heterozygous ?

Answer 12

When the copies of the gene (alleles) present on each of a pair of homologous chromosomes are different.

Question 13

What is polymorphism?

Answer 13

A polymorphism is a difference in DNA that is observed at a frequency of equal or greater to 1% within a population

Question 14

What is a mutation?

Answer 14

A mutation is a difference in DNA that is associated with disease.

Question 15

What is the haplotype?

Answer 15

The haplotype is a set of DNA variations or group of alleles that are inherited together.

Question 16

What are germline cells?

Answer 16

Those that contain and transmit genetic information from generation to generation.

Question 17

What are somatic cells?

Answer 17

All cells other than germline.

Question 18

What are some sources of genetic difference?

Answer 18

Independent assortment of homologous pair of chromosomes occurs in meiosis.

Random fertilisation also contribute to the differences.

Differences also arise due to crossing over. Homologous chromosomes exchange genetic information by recombination, occurs during meiosis.

Damage to chromosome ends can lead to their fusion and incorrect separation during meiosis causing gene amplification and loss.

Question 19

What does variation in the regulatory region cause?

Answer 19

Can either cause alterations in efficiency of:

Transcription
Translation
Splicing

Question 20

What does variation in the coding region cause?

Answer 20

Can affect the amino acid sequence of the protein to alter its functional properties.

Can have an effect on the rate of folding of the protein (a consequence of codon abundancy).

Can have an effect on protein stability.

Question 21

What are the types of genetic variation?

Answer 21

Single nucleotide polymorphisms.

Base deletion or insertion.

Microsatellites.

Minisatellites.

Copy number variations.