- identify chromosomal aberrations - chromosome gene mapping

L17 - chromosomal mutations Flashcards by megan falco

what is P

short arm of chromosome

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what is q

long arm of chromosome

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what separates the arms of chromosome

centromere

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define telomere

repeated DNA sequence that protects end of chromosomes

TTAGGG

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define sub-telomere

region between telomere and protein region of chromosome

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role of telomerase?

DNA pol 2 cant synthesise end of lagging strand so telomerase does this

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what do we call a chromosome where p&q arm are equal

metacentric

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put these in order of shrinking p arms 
acrocentric
metacentric 
telocentric 
submetacentric

metacentric
submetacentric
acrocentric
telocentric

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what is the most common type of chromosome in humans

submetacentric

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what is cytogenetics

study of chromosome variations that cause certain traits / illesses

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does
heterochromatin
euchromatin
stain light or dark

heterochromatin - dark

euchromatin - light

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what is karyotyping

process of pairing and ordering all of an organisms chromosomes

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what is G banding

staining chromosomes with giesma dye after addition of trypsin

shows how condensed the chromosomes are at different times (eg stages of mitosis)

these bands can be used to identify regions of the chromosome

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what is FISH

fluorescent in situ hybridization

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uses of FISH

identify chromosomal aberrations

- chromosome gene mapping

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explain process of FISH

what do we look for in FISH experiment?

two fluorescent probes used, one control binds to DNA outside target region, one binds to target region

did probe bind
where did probe bind
if probe also bound to other unexpected regions

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define constitutive chromosome abnormality

all tissues have same chromosomal abnormality

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define acquired chromosome abnormality

only one organ / tissue has chromosome abnormality

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define homogeneous chromosome abnormality

all cells carry abnormality

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define mosaic chromosome abnormality

only some cells carry abnormality

define numerical chromosome abnormality

abnormality what changes number of chromosomes (46)

define structural chromosome abnormality

abnormalities include

missing/extra/changed genetic material within a chromosome

list the types of numerical chromosome abnormalities

polyploidy

aneuploidy

what is euploidy

normal no. and sets of chromosomes

what is polyploidy

presence of more than 2 complete sets of chromosomes | eg normal 46, polyploidy 92

what is aneuploidy

additional / missing individual chromosomes

what are the two types of structural chromosome abnormalities

balanced rearrangements | unbalanced rearrangements

describe unbalanced chromosome rearrangements

additional / missing genetic info on a chromosome | eg insertion/deletion

describe balanced chromosomal rearrangements

no gain / loss of DNA | eg translocation, inversion

what is triploidy tetraploidy

types of polyploidy 3 sets of chromosomes (69) 4 sets of chromosomes (92)

what are the types of aneuploidy and how many C's in each

monosomy - 45 trisomy - 47 nullisomy - 44

what is nullisomy

when pair of homologous chromosomes missing

when does non disjunction most frequently occur

anaphase 1

describe translocation chromosome abnormality

portion of one C transferred to another

describe reciprocal translocation chromosome abnormality

segments from two different C exchanged

describe robertsonian translocation chromosome abnormality

entire C arm attached to another C arm at centromere

what is sub-microscopic deletion

deletion of less that 5mb pairs | too small to be detected by microscope

what is inversion chromosome abnormality

portion of chromosome breaks off, turns around then reattaches upside down genetic info inverted

what is paracentric inversion

an inversion that doesnt include centromere

what is pericentric inversion

inversion that includes centromere

describe insertion chromosome abnormality

part of a C deleted and inserted into another C

what is ring chromosome abnormality

part of C breaks off and forms a ring | can occur with / without loss of genetic info

what is isochromosome chromosome abnormality

where the p arms attach to eachother and q arms attach to eachother instead to pq

what is NAHR and when does it occur

non allelic homologous recomb | between similar sequences of DNA that aren't alleles

what is uniparental disomy

when 2 copies of a C come from one parent

what are trinucleotide repeats

DNA segment that contains repeat of 3 nucleotides (eg CAGCAGCAGCAG) if this is passed to offspring the no. of repeats may differ

define synteny

genes occurring on same chromosome

what is trisomy 21

down syndrome