T5 Applied lecture Flashcards
define aneuploidy
abnormal number of certain chromosomes
define karyotpye
organized display of homologous pairs of chromosomes + sex chromosomes
what is amniocentesis? chorionic villus sampling?
fetal development tests
Amniocentesis
- sample amniotic fluid (placental fluid)
- takes several weeks because cells must be cultured
CVS
- sample chorionic villus tissue (placental tissue)
- takes several days
how do you make a karyotype?
- blood drawn, take a few drops as samples
- phytohemagglutinin added to stimulate mitosis
- incubate @ 37˚C for 2-3 days
- add Colcemid for 1-2 hours to stop mitosis in metaphase
- transfer cells to tube with low salt solution to get rid of blood cells.
- centrifuge
- add fixative
- stain slide, microscope
kleinfelter syndrome
- males that have extra X chromosome (XXY)
- feminine body structure
- small, sterile testes
trisomy
3 copies of a certain chromosome
Down syndrome
trisomy of chromosome 21
Patau syndrome
trisomy of chromosome 13
- severe cognitive disability
- cleft plalate
- deaf
- malformed organs
Edward’s syndrome
trisomy of chromosome 18
- small newborns
- low set ears, webbed neck, receding chin
- organ malfunction
Turner syndrome
XO female
- monosomy (Y chromosome)
- short stature, webbed neck
- sex organs don’t mature, sterile
triple X syndrome
XXX
- normal phenotype, fertile
Jacob’s syndrome
XYY
- normal male but much taller than average
cancer + aneuploidy
mitoic chromosome instability linked to many cancer cells (missing or too many chromosomes)
monosomy
missing chromosome
alleles for sex-linked disorders
Haemophilia: HM, hm
Colour Blindness: CB, cb
Dystrophin: D, d
HPRT-1: H, h
