Zusammenfassung der Ressource
Th2L03 Human
karyotype
- 46 chromosomes
- 23 from each parent
- 22 pairs of autosomes
- One pair of sex
chromosomes (XX or
XY)
- Assessing chromosomes
- Staining from metaphase
spreads
- G-banding
- Chromosomes are stained with
Giesma dye to expose light and
dark bands
- Pattern is
characteristic for
each chromosome
pair
- Cytogenetics
- study of genetic component of a cell through the
visualisation and analysis of chromosomes
- Human chromosomes are characterised by
- Size
- Short arm of chromosome, p
- Long arm of chromosome, q
- Pattern of G-bands
- Location of the centromere
- Metacentric chromosome
- Chromosome in which the two chromosome
arms are approximately the same length and
centromere is located in the middle of the
chromosome
- e.g. chromosome 3
- Submetacentric chromosome
- Chromosome in which the centromere is
displaced toward one end, producing a short
arm and a long arm
- e.g. chromosome 17
- Acrocentric chromosome
- Characterized by the centromere position very
near the end of the chromosome with the
short arm composed of highly repetitive
(satellite) DNA
- Stalks formed
- Consequence of abnormal
karyotype (out of 1,000,000
conceptions)
- 850K live births
- 75K have chromosomal abnormalities
- 39K trisomics
- Humans who have
gained an extra autosome
- do not survive development
minus a few exceptions on the
smallest chromosomes
- Trisomy 13, 18, 21
- 13.5K XO
- 12,750 triploids
- a polyploid that has three
complete haploid sets of
chromosomes
- 4,5 K tetrapolids
- organisms with 4 haploid
chromosome sets
- 5,2K other
- 833K children
- 17K perinatal
deaths(around the time
of birth)
- 150K
spontaneous
abortions