Cause and Effects of Variation in the Genome Flashcards Preview

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Flashcards in Cause and Effects of Variation in the Genome Deck (18):
1

What are some of the effects of altered proteins/ control of genes

Normal variation
Different response to medication
Likelihood of disease
Genetic condition

2

What are polymorphisms

Non-harmful mutation in non-functional DNA
Doesnt alter protein function

3

What are microsatellites

Tandem repeats of 2-6 BP

4

What are minisatellites

Tandem repeats of 10-60 BP

5

How does the Polymerase chain reaction work

Heat to denature DNA. Primers put in. Heat stable polymerase then builds the complementary chain

6

What is the size of DNA fragments limited by

Polymerase enzyme

7

How do you define length of amplifier

dDistance between annealed primers

8

What is the Sanger method

Anneal specific oligonucleotide primer to each template strand.
Strand synthesis catalysed by DNA polymerase, dNTPs and ddNTPs
ddNTPs = No 3 prime hydroxyl group so next nucleoside trisphosphate cannot bind. Fluorescently tagged

9

How could errors in DNA replication & meiotic cell division cause human disease

Meiosis = transmitted to children
DNA replication = change in base sequence
Crossing over = structurally abnormal chromosomes
Dealing out chromosomes = numerical abnormalities

10

What are the endogenous mechanisms causing mutations

Depurination = spontaneous fission of link between purine base and sugar
Deamination = cytosine deaminates to uracil
Reactive O2 = attack purine/pyrimidine rings
C methylated to 5-methyl-cytosine which deaminates to thymine

11

What are the extracellular agents that cause mutations

UV = Cross linking of adj thymines to form stable dimer
Chemicals
Ionising radiation = break DNA

12

What is germline mutation

Present in eggs/sperm
Heritable

13

What is somatic mutation

Non-germline tissue
Non-heritable

14

What is the DNA mismatch repair

Back-up to DNA polymerase

15

What occurs if protein complex recognise mismatch

Excise mismatched strand + Re-synthesise strand

16

What occurs if there is mutation in mismatch repair genes

Accumulation of permanent somatic mutations.

17

How is damage due to ionising radiation and reactive O2 repaired

Broken ends processed by nuclease
Ends joined by DNA ligation
Break repaired but deletion of nucleotides at repair site

May use homologous chromosome to synthesise missing DNA = homologous recombination

18

What are some of the types of DNA mutations

Silent Mutations = change in BP but not aa
Missense mutation = change in BP and aa
Nonsense mutation = Change in BP leading to STOP codon
Splice site mutation = prevent correct splicing
Frameshift mutation
Copy number variants