Genetics Flashcards

Question

Reciprocal translocations are when...

Answer 1

Segments from two different chromosomes have been exchanged

Answer 2

A chromosome attaches to another chromosome at the centromere Only occurs with 13, 14, 15, 21, 22 - two acrocentric chromosomes stuck end-end creating a normal phenotype

Answer 3

Turners syndrome 45XO

Answer 4

Downs syndrome

Answer 5

DNA probes specifically bind to areas of individual chromosomes and apply a fluorescein stain to make the chromosome visible Useful for detecting aneuploidies

Answer 6

Genomewide search to detect polymorphisms using dye and a scanner to show abnormalities between the sample and a reference (QUANTITIES)

Answer 7

Forces bands to appear on chromosomes using stains, helping to identify particular genetic diseases - unique pattern of bands for each chromosome

Answer 8

Edwards syndrome

Answer 9

Klinefelters syndrome

Answer 10

PCR - original DNA strand is duplicated and then copies are made increasing the mutation which is detected when compared to the trace NGS - DNA fragmented and rebuilt using the reference to show mutations

Answer 11

MISSENSE single nucleotide change creates a codon that codes for a different AA NONSENSE single nucleotide change codes for a premature stop codon INSERTION DELETION

Answer 12

MUTATION POLYMORPHISM VARIANT OF UNKNOWN SIGNIFICANCE

Answer 13

There is one faulty copy of the gene Seen in all generations 50% risk of affected child if parent affected

Answer 14

There are 2 faulty copies of the gene Often only one generation affected 25% risk of affected child if parents are carriers Increased likelihood if parents are related

Answer 15

The disease is carried on the X-chromosome - only 50% of male children of a female carrier affected - 50% of female children of a female carrier affected - All male children of a male carrier normal - All female children of a male carrier will be carriers

Answer 16

Female carrier shows mild features of X-linked disease

Answer 17

X INACTIVATION: one X chromosome of females randomly inactivated using XIST gene of XQ13 via METHYLATION

Answer 18

DNA transcription - chemic modification that does not change base sequence but interacts with histones on DNA

Answer 19

SKEWING: Inactivation of one X chromosome favoured over another - mutation in XIST gene - results in uneven number of cells with X chromosome inactivation

Answer 20

The likelihood of having the disease given you have the genetic mutation

Answer 21

Autosomal dominant Autosomal recessive X-linked Mitochondrial

Answer 22

a) High - controlled by mutation in single gene with a small environmental input b) Low - genetic change attributed to environmental input

Answer 23

Common disease causing variants will be found in all human populations which show a disease but not necessarily expressed in phenotype

Answer 24

Variation in gene expression depending on which parent you inherit the gene from e.g. in Angelman's syndrome, mother's UBE3A works fine but father's is methylated - controlled by methylation

Answer 25

Diseased mitochondria passed from mother to child

Answer 26

Different daughter cells contain different proportions of mutant mitochondria (similar to mosaicism)

Answer 27

Occurs when cells within the same person have a different genetic makeup (causes cancer)

Answer 28

Functional modifications to the genome that do not involve a change in the nucleotide sequence

Answer 29

Between G2 and M Between G1 and S

Answer 30

Promote cell division

Answer 31

Inhibit cell division

Answer 32

False 2 copies required (2 Hit Hypothesis)

Answer 33

False More usually multifactorial

Answer 34

a) BRCA1 mutation b) mother/sister breast cancer at 45 c) mother with breast cancer at 70