Lecture 5 - Development Genetics

Question 1

What are genes named after?

Answer 1

Protein product or phenotype (whichever came first)

Question 2

What is italicised in nomenclature?

Answer 2

Species name & gene name

Question 3

What is not italicised in nomenclature?

Answer 3

Proteins

Question 4

What are examples of radiation that cause mutations?

Answer 4

• ultraviolet light
• x-rays
• radioactivity

Question 5

What are examples of chemicals that cause mutations?

Answer 5

• base analogues
• base modifiers
• intercalating agents

Question 6

What are different types of mutations that can occur?

Answer 6

• point mutations (single base-pair)
• deletion
• insertion
• translocation

Question 7

What are germline mutations?

Answer 7

Inherited mutations (sperm or oocyte)

Question 8

What are somatic mutations?

Answer 8

In our body

Question 9

What is the name given to the production of mutations in model organisms?

Answer 9

Mutagenesis

Question 10

Define the consequence of gene knockout?

Answer 10

This completely removes the gene to determine its function

Question 11

Define the consequence of gene replacement (knock-in)?

Answer 11

Usually makes small changes to the endogenous gene

Question 12

What can CRISPR be used for?

Answer 12

can be used to knock-out or knock-in.

Question 13

What is the advantage of using CRISPR?

Answer 13

It works in any organisms

Question 14

What are the 3 ways mutations affect genes?

Answer 14

• changes in regulatory sequences
• changes in non-coding sequences
• changes in the coding sequences

Question 15

How can mutations affect changes in regulatory sequences?

Answer 15

changes DNA, that affects transcription - can lead to less protein being created

Question 16

How can mutations affect changes in non-coding sequences?

Answer 16

Affect RNA splicing, stability or translation

Question 17

How can mutations affect changes in the coding sequence?

Answer 17

May alter amino acid, affecting folding of the protein, or create premature stop-codon = truncated protein

Question 18

What is the word to describe a mutation that a single amino acid substituted?

Answer 18

Missense (point) mutation

Question 19

What is the word to describe a mutation that causes a stop codon?

Answer 19

Nonsense

Question 20

What is a domain?

Answer 20

Functional unit in a protein

Question 21

What is a dimer?

Answer 21

When 2 of the same protein bind together

Question 22

What is a conformational change?

Answer 22

A change in protein structure

Question 23

What is the process by which 2 copes of the same protein interact?

Answer 23

Dimerisation

Question 24

What is an amorphic mutation (A non-functional version of protein/non-functioning)?

Answer 24

A missense mutation that completely inactivated the DNA binding domain.

Question 25

What occurs if there is one mutation in an amorphic mutation?

Answer 25

Normally there’s enough gene product from one wild-type copy - Haplosufficient

Question 26

What occurs if there is two mutations in an amorphic mutation?

Answer 26

Strong phenotype due to no transcriptional activation. This is recessive.

Question 27

What is a hypomorphic/weakened mutation?

Answer 27

A missense mutation that weakens the DNA binding domain

Question 28

What occurs if there is one mutation in a hypomorphic mutation?

Answer 28

There is normally enough green product from one wild-type copy. The mutant form many also diverse with the wild type and still activate transcription.

Question 29

What occurs if there is two mutation in a hypomorphic mutation?

Answer 29

Mild phenotype due to poor transcription activation. The dimer forms on DNA but is often falling off. This is recessive.

Question 30

What is an antimorphic mutation?

Answer 30

A missense mutation that destroys the dimerisation domain

Question 31

What occurs if there is one mutation in an antimorphic mutation?

Answer 31

The mutant form binds DNA but doesn’t dimerise with the wild type & thus doesn’t go through a conformational change to become active.

Question 32

What occurs if there is two mutation in an antimorphic mutation?

Answer 32

Completely inactive

Question 33

What is a hypermorphic mutation?

Answer 33

A missense mutation that results in activation that is independent of dimerisation

Question 34

What occurs if there is one mutation in a hypermorphic mutation?

Answer 34

The mutant form binds DNA that is active all the time. We call this CONSTITUTIVELY ACTIVE. This increases the overall activation of transcription. This is dominant.

Question 35

What occurs if there is two mutations in a hypermorphic mutation?

Answer 35

The same - DNA active all the time

Question 36

What is the difference between amorphic & antimorphic mutations?

Answer 36

Amorphic - recessive: 1 mutant would still allow wild-type to transcribe

Antimorphic - dominant negative: 1 mutant will poison wild-type, as it is a competitive inhibitor.

Question 37

What are the 3 types of loss-of-function mutations?

Answer 37

• amorphic
• hypomorphic
• antimorphic

Question 38

What is a type of gain-of-function mutation?

Answer 38

Hypermorphic

Question 39

What is the name of different mutations in the same gene?

Answer 39

Alleles

Question 40

How do you create a GFP (green fluorescent protein protein) transgenic line?

Answer 40

1. genomic DNA with all of the regulatory elements - this may include replacing the stop codon with a GFP gene.
2. genetically engineered GFP onto the end of the last exon (gene fusion) or replace the gene (reporter construct).
3. Re-introduce this into the animal.

Question 41

What are 2 uses of GFP transgenic lines?

Answer 41

• to follow expression of a gene or to follow the behaviour of cells in vivo.
• to follow sub cellular localisation of a protein