Genetics

Question 1

what is the backbone of DNA

Answer 1

sugar backbone- 2-deoxyribose

Question 2

how many base pairs in the human genome

Answer 2

3 000 000 000

Question 3

how many genes in the human genome

Answer 3

30 000

Question 4

how many polymorphisms usually in a genome

Answer 4

3 000 000

Question 5

what tests does array genomic hydridisation tests (aCGH) include and what do they test

Answer 5

standard kaytotype- entire chromosome

FISH- 5-10 megabases

multiplex ligation dependent amplification- 1000 bases

Question 6

what are the types of next generation tests

Answer 6

muliplex ligation dependent amplification

PCR amplification and sequencing

Question 7

what tests can detect a point mutation

Answer 7

PCR amplification and sequencing

Question 8

what genetic changes can karotype detect

Answer 8

aneuploidy (abnormal number of chromosomes)

chromosome translocation

deletion

Question 9

what genetic changes can fish detect

Answer 9

deletion and microdeletion

Question 10

what can mulitplex ligation dependent amplification detect

Answer 10

deletion of part of a gene

Question 11

what is the difference between a balanced and an unbalanced chromosomal translocation

Answer 11

balanced- even exchange of material with no genetic information extra or missing

unbalanced- unequal transition causing extra or missing genes

Question 12

what does chromosome microarray array genomic hybridisation let you see

Answer 12

sub microscopic deletions/ duplications of chromosomal material across the whole genome

compares control DNA to patients (half as much= deletion, 50% more= duplication)

Question 13

does chromosome microarray array genomic hybridisation detect balanced or unbalanced chromosomal rearrangements only

Answer 13

UNBALANCED

Question 14

what indicates a deletion in aCGH

Answer 14

half as much DNA

Question 15

what is the most sensitive test for looking at whole chromosomes

Answer 15

aCGH

Question 16

what does a red dot mean on fish

Answer 16

gene that is missing on other chromosome- deletion

Question 17

what is considered the normal genome

Answer 17

commonest form of the gene sequence in caucasian americans

Question 18

what can help indentifying polymorphisms that might be disease causing

Answer 18

comparing the DNA of the patient to their parents DNA

Question 19

how much of genome codes are exons

Answer 19

1-2%

Question 20

where do splice site mutations usually occur

Answer 20

1 or 2 bases into intron

Question 21

how do you know that a polymorphism is disease causing

Answer 21

in gene that matches phenotype
has affect on gene function
not listed as a polymorphism (in significant amount in population)
it is an evolutionary conserved bit of gene
it is de novo in child
or is present in affected family members

Question 22

what is a missense mutation

Answer 22

point mutation where a single bases creates a different amino acid

Question 23

what is a triplet expansion mutation

Answer 23

where an amino acid is repeated (the cat cat sat on the mat)

Question 24

what are the features of kabuki make up syndrome

Answer 24

speech delay 
cleft palate 
unusual eyes and eyebrows 
tendency to drool 
short 2nd phalange of 5th finger

Question 25

what is the best test to identify de novo mutations in a child

Answer 25

next generation sequencing (can also test parents to exclude variants)

Question 26

what is the biggest cause of mutations in a child

Answer 26

increase in paternal age (age of father)

Question 27

what does tuberous sclerosis cause

Answer 27

seizures