Genetic variation

Question 1

only … and … are genetically identical

Answer 1

clones and monzygotic twins

Question 2

what could be different about the DNA of monozygotic twins

Answer 2

epigenetic inheritance e.g. chromatin and histone modifactions, methylation

Question 3

types of genetic variation

Answer 3

1. single nucleotide polymorphisms (SNPs) 2. Indels 3. copy number variation 4.strucutral rearrangements 5.

Question 4

polymorphisms

Answer 4

two or more alleles of a gene, common in a population

Question 5

types of DNA sequencing

Answer 5

sanger next generation

single molecule

Question 6

what are copy- number generations caused by ?

Answer 6

large insertion/deletions in one chromosome

Question 7

copy number variation (CNV)

Answer 7

is defined as a phenomenon in which sections of the genome are repeated and the number of repeats in the genome varies between individuals in the human population.

Question 8

structural rearrangements of chromosomes

Answer 8

translocations

inversion

Question 9

SNPs

Answer 9

single nucleotide polymorphisms- single base pair changes -occurs at a specific position in the genre, where each variation is present to some appreciable degree within a population

Question 10

Indels

Answer 10

Insertion and deletions

Question 11

most genetic variation has…

Answer 11

no phenotypic effect

Question 12

how can SNPs be detected

Answer 12

DNA hybridisation technique

Question 13

how deletions differ to SNP

Answer 13

more than one pair is deleted

Question 14

example of an SNP which causes diseasw

Answer 14

eg. a single base pair change can cause sickle cell anaemia

Question 15

Indels with phenotypic effect -deletions -insertions

Answer 15

deletion: CF- 3 base pairs
insertion: one base pair can cause albinism

Question 16

how many indwells have been identified in human genomics

Answer 16

4 x10^5

Question 17

percentage of indwells which are tandem repeat expansion polymorphisms

Answer 17

30%

Question 18

what are Short Tandem repeats (STRs)

Answer 18

multi-allelic and used in genetic profiling accordion-like stretches of DNA containing core repeat units of between two and seven nucleotides in length that are tandemly repeated from approximately a half dozen to several dozen times

Question 19

STRs

Answer 19

short tandem repeats

Question 20

STRs are also known as

Answer 20

minisateellites

Question 21

STRs are ..

Answer 21

unique in everyone humans

Question 22

how can indwells cause a new protein

Answer 22

by coding for a stop codon, by changing the amino acid sequence, by causing a frameshift

Question 23

why do indwells normally disrupt protein structure

Answer 23

if in coding region it may cause a frame shift due to the non-overlapping nature of dna

Question 24

effects of base substitutions (4)

Answer 24

silent neutral mis-sense nonsense

Question 25

effect of genetic variation on INTERGENIC REGIONS

Answer 25

Often no phenotypic effect- silent

Question 26

effect of genetic variation on non coding regions of genes (introns, promotor, UTRs):

Answer 26

may be silent, however may effect gene expression

Question 27

effect of genetic variation on protein coding regions

Answer 27

various effects

Question 28

Sanger method

Answer 28

Method: in vitro DNA synthesis with base specific chain- termination inhibitors. Detection: gel electrophoresis Typical length of sequence: 800 bases -accurate, low throughput

Question 29

Next generation sequencing

Answer 29

Method: massive parallel in vitro DNA synthesis Detection: fluorescence detection of incorporated nucleotides Typical length of sequence: 100 bases -extremely high throughput