2. What are
karyotypes?
Karyon = kernel, seed, or nucleus
the number and appearance of chromosomes in the
nucleus of a eukaryotic cell
Chromosomes: an organized structure of DNA &
protein found in cells
23 pairs (23 from each parent)
karyogram--compare pairs, sizes, position of
centromere
Giemsa dye-staining
3.
4. What are karyotypes even
used for? (or karyograms of karyotypes) are often
Karyotypes
used to determine things about a fetus.
A blood sample is taken from the mother, and by
looking at the karyotype, chromosomal abnormalities
can be determined.
Observed to see chromosomal and genetic differences
between species and within the same species over
time.
# of chromosomes, the shape/size of chromosomes,
and sex of an individual can be observed among other
things.
5. How karyotyping is
done.
Staining
Giemsa dye after cell division
Can use almost any cell or tissue
1. Blood drawn
2. Amniocentesis (to test amniotic fluid)
3. Sample grows
4. Stained
6.
7. History
Karl Wilhelm von Nägeli first observed chromosomes
(via plant cells) in 1842
1920’s-T.S. Painter, XX/XY system for determining sex
(not XX/X0)
48 chromosomes
1955/1956, Joe Hin Tijo correctly determined # of
chromosomes (46)
9. Abnormalities/Disea
ses
Turner Syndrome
missing or incomplete X chromosome
develop as females
Down Syndrome
error in cell division...extra 21st chromosome
impairments in both cognitive ability and physical growth
Patau Syndrome
trisomy of chromosome
occurs in approximately one out of every ten-thousand to sixteen-thousand
infants
17. To get a karyotype of the fetus,
a ___ sample is taken from
the mother.
Blood
18. Define “amniocentesis”
the sampling of amniotic
fluid using a hollow needle
inserted into the uterus, to
screen for developmental
abnormalities in a fetus
19. Define “trisomy”
a condition in which an
extra copy of a
chromosome is present in
the cell nuclei, causing
developmental
abnormalities
20. Which disease is caused by a missing
or incomplete X chromosome?
Turner Syndrome