genetics Flashcards
what is a acrocentric chromosome
lacks a short arm
what is a balanced chromosomal arrangement
correct amount of chromosomal material despite rearrangement
what is unbalanced chromosomal arrangement
extra or missing chromosomal material
chromosomal arrangement of downs syndrome
trisomy 21, 3 copies of chromosome 21 (aneuploidy)
47XY +21
what is edwards syndrome
trisomy 18
what is turner syndrome
45 X (missing a sex chromosome)
what is FISH
probe DNA fluorescently labelled and hybridised into actual DNA to show position of certain genes, DNA must be denatured for hybridisation
- not effective for small chromosomal changes
what is aCGH
molecular cytogenic technique, chromosomes do not need to be seen
can only be used to detect imbalance in chromosomal material
can detect any size of imbalance
what causes mosaicism
post zygotic mutations
what is mendelian disorders
disorders caused by changes to a single gene
examples of mendelian disorders
CF, sickle cell, duchene muscular dystrophy
