About one week according to:
http://downsyndrome.about.com/od/diagnosingdownsyndrome/ht/Howkaryotype_ro.htm
Or longer, depending on the test, according to:
http://www.sydneygenetics.com/FAQs/Cytogeneticschromosometestkaryotype/tabid/539/Default.aspx
A karyotype.
in the metaphase
A karyotype is a visual display of the chromosomes arrangeed by size, shape, and banding pattern.
A picture of chromosomes is called a "karyotype."
Karyotype
They take pictures of the chromosomes during mitosis, when the chromatin condenses. Then they pair each chromosome together on the computer.
A karyotype is the number and visual appearance of the chromosomes in the cell nuclei of an organism or species. A karyotype indicates gender, and whether there are any chromosomal abnormalities.
This is known as a karyogram.
Karyotype
The karyotype of the asexual organism would not contain homologous chromosomes
A karyotype is an organized arrangement of a person's chromosomes. In a karyotype, chromosomes are sorted and numbered by size, from largest to smallest.
The karyotype of the asexual organism would not contain homologous chromosomes