Prenatal Genetics Flashcards
What is chromatin?
What are nucloeomes?
How many histones make up a nucleosome?
Which histones pair up?
Describe chromatin compaction
Compare and contrast heterochromatin and euchromatin
What are chromatosomes?
How are metaphase chromosomes prepared?
What is G band staining?
What are the types of FISH? (There are 5 we discussed)
1.Whole Chromosome FISH
2. Spectral karyotyping (SKY)
Locus specific FISH which includes
3. Copy Number Variation (CNV) FISH
4. Break-apart FISH
5. Fusion FISH
Name and describe the nucleosome histones
H2A - DIMER
H2B - DIMER
H3 - TETRAMER
H4 - TETRAMER
Differentiate nucleosome from chromatosome
What is the function of colcemid in metaphase chromosome prep?
What is the function of trypsin in metaphase chromosome prep?
What is the function of trypsin in Geimsa staining?
List and describe the 4 chromosome shapes
Metacentric – centromere located centrally, the p and q arms are approximately the same length.
Submetacentric - centromere is located off center; the q arm is slightly longer than the p arm
Acrocentric - the centromere is located nearer one end of the chromosome; the q arm is significantly larger than the p arm.
Telocentric – the centromere is the distal end of the chromosome and there is no p arm; not normally found in humans
List the somatic aneuploidies studied
Trisomy 21 - Downs syndrome
Trisomy 18 - Edwardsyndrome
Trisomy 13 - Patau syndrome
List the sex-linked aneuploidies studied
Monosomy X - Turner syndrome
XXY - Klinefelter syndrome
Trisomy X
XYY - Jacobs syndrome
List the sex chromosome STRs and their associate gene locations
DXS1187 Xq26.2
DXS6803 Xq13
HPRT Xq26.2
TAF9L chromosome 3 (116 bp) and chromosome X (121 bp) female 1:1 ratio male 2:1 ratio
AMEL chromosome X and Y, encodes amelogenin female 1 peak 104 bp male 2 peaks 104, 110
SRY Yp11.31, a gene that encodes a transcription factor indicates presence of Y chromosome, male 248 bp
