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Flashcards in mutations and genetic analysis Deck (32):
1

what are the 3 types of chromosomal abnormalities?

numerical, structural and mutational abnormalities

2

what makes up around 50 percent of chromosomal abnormalities?

first trimester miscarriages

3

what is the aetiology of patau syndrome?

trisomy 13

4

what is the aetiology of edwards syndrome?

trisomy 18

5

what is the aetiology of downs syndrome?

trisomy 21

6

what is the aetiology of klinefelter syndrome?

Y chromosome along with 2 X chromosomes

7

what is the aetiology of turner syndrome?

monosomy - only a single x chromosome

8

what is non-disjunction?

failure of homologous chromosomes or sister chromatids to separate properly during cell division.

9

what are some symptoms of turner syndrome?

females are short of stature and infertile
neck webbing
widely spaced nipples

10

what are some symptoms of klinefelter syndrome?

tall stature, long limbs
infertile males with small testes
gynaecomastia in around 50%
mild learning difficulties

11

what are some examples of structural abnormalities in DNA?

balanced or unbalanced rearrangements
translocations
deletions
insertions
inversions

12

what are the two types of translocations?

reciprocal - involves breaks in two chromosomes with the formation of two new derivative chromosomes
robertsonian - fusion of two acrocentric chromosomes

13

what are some outcomes of unbalance translocation?

partial trisomy
partial monosomy

14

what is lost in robertsonian translocation?

the two short arms of the acrocentric chromosome, however, no genetic information is lost

15

what are the 2 classifications of genetic mutation?

non-coding
coding

16

what types of coding mutations are there?

silent
missense
nonsense
frameshift

17

what causes frameshift mutations?

insertion and deletion

18

what are the types of point mutation?

transitions and transversions

19

what classifies a point mutation as a transition?

purine > purine or pyrimidine > pyrimidine

20

what classifies a point mutation as a transversion?

purine to pyrimidine or pyrimidine to purine

21

what are some methods used to detect mutations?

PCR
gel electrophoresis
restriction fragment length polymorphism (RFLP) analysis
amplification refractory mutation system (ARMS)
DNA sequencing

22

what are the 3 steps of PCR and what temperatures do they take place at?

denature - 93-95 celsius
anneal- 50-70 celsius
extend - 70-75 celsius

23

what are the steps in gel electrophoresis?

separate DNA fragments by size
apply an electric field (DNA is negatively charged)
separation occurs through an agarose gel matrix
fragments of DNA are then visualized

24

what are some advantages of gel electrophoresis?

speed
ease of use
sensitive
robust

25

what are some applications of PCR?

DNA cloning
DNA sequencing
gene identification
forensic medicine
detection of mutations

26

what are some advantages of ARMS?

cheap
labelling not required

27

what are some disadvantages of ARMS?

need sequence information
limited amplification size
limited amounts of product
infidelity of DNA replication
electrophoresis required
primer design critical

28

what are restriction endonucleases?

enzymes from bacterial cells
protective mechanism
degrade DNA of invading viruses
recognise specific DNA sequences
always cut the DNA at same site

29

what are some advantages of RFLP?

simple
cheap
non radioactive

30

what are some disadvantages of RFLP?

requires gel electrophoresis
not always feasible

31

what are some advantages of gene sequencing?

best option for detection of mutation
automated
can sequence a huge length of base pairs

32

what are some limitations of gene sequencing?

expensive equipment
poor quality sequence read.