mutations and genetic analysis Flashcards

1
Q

what are the 3 types of chromosomal abnormalities?

A

numerical, structural and mutational abnormalities

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2
Q

what makes up around 50 percent of chromosomal abnormalities?

A

first trimester miscarriages

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3
Q

what is the aetiology of patau syndrome?

A

trisomy 13

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4
Q

what is the aetiology of edwards syndrome?

A

trisomy 18

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5
Q

what is the aetiology of downs syndrome?

A

trisomy 21

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6
Q

what is the aetiology of klinefelter syndrome?

A

Y chromosome along with 2 X chromosomes

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7
Q

what is the aetiology of turner syndrome?

A

monosomy - only a single x chromosome

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8
Q

what is non-disjunction?

A

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

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9
Q

what are some symptoms of turner syndrome?

A

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

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10
Q

what are some symptoms of klinefelter syndrome?

A

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

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11
Q

what are some examples of structural abnormalities in DNA?

A
balanced or unbalanced rearrangements
translocations
deletions
insertions
inversions
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12
Q

what are the two types of translocations?

A

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

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13
Q

what are some outcomes of unbalance translocation?

A

partial trisomy

partial monosomy

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14
Q

what is lost in robertsonian translocation?

A

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

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15
Q

what are the 2 classifications of genetic mutation?

A

non-coding

coding

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16
Q

what types of coding mutations are there?

A

silent
missense
nonsense
frameshift

17
Q

what causes frameshift mutations?

A

insertion and deletion

18
Q

what are the types of point mutation?

A

transitions and transversions

19
Q

what classifies a point mutation as a transition?

A

purine > purine or pyrimidine > pyrimidine

20
Q

what classifies a point mutation as a transversion?

A

purine to pyrimidine or pyrimidine to purine

21
Q

what are some methods used to detect mutations?

A

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

22
Q

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

A

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

23
Q

what are the steps in gel electrophoresis?

A

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
Q

what are some advantages of gel electrophoresis?

A

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.