Introduction to Genomics

Question 1

What is the role of genomics in healthcare?

Answer 1

Genomics has the potential to transform healthcare with more accurate diagnosis of a broader range of diseases with a genetic basis and allows patients to know their likelihood of developing one of these diseases.

Question 2

What is genomics?

Answer 2

Structural and functional mapping of genomes and their evolutions.

Question 3

What is a chromatin?

Answer 3

Consists of DNA and protein.

Found inside the nucleus of a cell, it is a bit of a ‘tangled mess’

Question 4

What are histones?

Answer 4

Histones help package and regulate the DNA in the chromatin.

Question 5

How many histones are there in a nucleosome?

Answer 5

8

Question 6

What is DNA made up of?

Answer 6

A sugar called deoxyribose

Question 7

How are the ‘rungs’ of the DNA ladder made?

Answer 7

Base pairs that weakly bond together to form these rungs.

They form a code which cells follow to make proteins

Question 8

What are the two types of nucleotides?

Answer 8

Purines (base pairs AG)

Pyrimidines (base pairs TC)

Question 9

What always pairs with A and what always pairs with G?

Answer 9

A always pairs with T (or U in RNA)

G always pairs with C

Question 10

How is RNA made?

Answer 10

DNA holds a code which is used to make RNA through a process called transcription.

Question 11

How does RNA make proteins?

Answer 11

Through a process called translation

Question 12

How do amino acids know when to stop translating?

Answer 12

There is a ‘stop’ codon = UAG which stops the translation

Question 13

How many amino acids are directly coded in the genome?

Answer 13

20 amino acids in the human body

Question 14

What are the 4 characteristics of a protein?

Answer 14

Non-polar side chains
Polar side chains
Acidic side chains
Basic (alkali side chains)

Question 15

What are the purpose of amino acids?

Answer 15

Amino acids do different ‘jobs’ in the final protein. If you change one of the amino acids in the sequence, then you could change the function of the protein.

Question 16

How many genes do we have approximately?

Answer 16

~21,000

Question 17

What are gene mutations?

Answer 17

Not all versions of a gene are the same, some genes will change causing mutations

Question 18

What are the 4 types of gene mutations

Answer 18

Gain of function mutations
Loss of function mutations
Lethal mutations
Ineffective mutations

Question 19

How does a single gene produce multiple proteins?

Answer 19

Through a process called alternative gene splicing

Question 20

What are the two types of proteins?

Answer 20

Proteins have structural and functional types

Question 21

What are some of the structural protein types?

Answer 21

Collagen
Elastin
Keratin

Question 22

What are some of the functional protein types?

Answer 22

Enzymes
Ion channels
Neurotransmitter receptors
Antibodies

Question 23

How do we changed the structure and function of a protein?

Answer 23

Through a process called translational modification

Question 24

What are the 4 steps of translational modification?

Answer 24

1. add carbohydrate parts
2. add lipid parts
3. modifying AA side chains
4. Adding chemical regulators

Question 25

What is a pseudogene?

Answer 25

Non-functional gene ('damaged' gene sequence)

Question 26

What are the key features of pseudogenes?

Answer 26

They either do not produce proteins or it is non-functional They lack key regulatory regions (e.g. missing introns or promoter) They have a start codon but a premature stop codon They may have a partially deleted gene sequence

Question 27

What are the two types of sexual reproduction?

Answer 27

Meiosis | Mitosis

Question 28

What is Meiosis?

Answer 28

Special cell division for production of gametes

Question 29

What are some other reasons for genetic variation?

Answer 29

Genetic recombination events Random crossovers Independent assortment of alleles/gene variants Random fertilisation

Question 30

What are some examples of mutagens?

Answer 30

Pollutants/environmental triggers Viral insertions Ultraviolet light Radiation

Question 31

What is a mutation?

Answer 31

Any heritable changes to DNA sequence

Question 32

What is an inconsequential mutation?

Answer 32

A mutation that leads to no net effect on the person

Question 33

What is an consequential mutation?

Answer 33

A mutation that does have an effect on a person (ranges from milk to severe to lethal)

Question 34

What is a loss/gain of function variant?

Answer 34

A gene product that either gains or loses some or all of its function

Question 35

What are the several different mechanism identified in a variant

Answer 35

Single nucleotide variants Intels (insertion or deletion) Structural variants Repeat variants

Question 36

What is a missense mutation?

Answer 36

a single nucleotide that has been substituted for a different one. The code has been changed so that they could specify a different AA

Question 37

What is a nonsense mutation?

Answer 37

A single nucleotide has been substituted for a different one. The code has been changed to STOP codon so that AA sequence of resulting proteins is truncated.

Question 38

What is a translocation?

Answer 38

A chromosomal abnormality

Question 39

What is an inversion?

Answer 39

Reversal of a genetic coding region

Question 40

What are copy number variants?

Answer 40

Deletions or duplication of coding region

Question 41

What are some categories of genetic variations ?

Answer 41

Missense and Nonsense variants Insertions/Deletions Single nucleotide variants

Question 42

What is the process of a blood test for a monogenic disorder?

Answer 42

1. take a sample of DNA (usually blood) 2. use gene-specific reactions to 'copy' the gene 3. Separate the 'copies' by size 4. If there is a gene deletion, the smaller copy will show up

Question 43

What are the benefits of new sequencing technology?

Answer 43

Much more rapid Highly automated Relatively inexpensive

Question 44

What is bioinformatics?

Answer 44

The analysis, storage, annotation and retrieval of genomic data.