Genetic variation Flashcards Preview

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Flashcards in Genetic variation Deck (29):
1

only ... and ... are genetically identical

clones and monzygotic twins

2

what could be different about the DNA of monozygotic twins

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

3

types of genetic variation

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

4

polymorphisms

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

5

types of DNA sequencing

sanger next generation

 

single molecule

6

what are copy- number generations caused by ?

large insertion/deletions in one chromosome

7

copy number variation (CNV)

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.

8

structural rearrangements of chromosomes

translocations

inversion 

9

SNPs

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

10

Indels

Insertion and deletions

11

most genetic variation has...

no phenotypic effect

12

how can SNPs be detected

DNA hybridisation technique

13

how deletions differ to SNP

more than one pair is deleted

14

example of an SNP which causes diseasw

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

15

Indels with phenotypic effect -deletions -insertions

deletion: CF- 3 base pairs

insertion: one base pair can cause albinism

16

how many indwells have been identified in human genomics

4 x10^5

17

percentage of indwells which are tandem repeat expansion polymorphisms

30%

18

what are Short Tandem repeats (STRs)

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

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STRs

short tandem repeats

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STRs are also known as

minisateellites

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STRs are ..

unique in everyone humans

22

how can indwells cause a new protein

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

23

why do indwells normally disrupt protein structure

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

24

effects of base substitutions (4)

silent neutral mis-sense nonsense

25

effect of genetic variation on INTERGENIC REGIONS

Often no phenotypic effect- silent

26

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

may be silent, however may effect gene expression

27

effect of genetic variation on protein coding regions

various effects

28

Sanger method

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

29

Next generation sequencing

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