Karyotyping Part 1 Flashcards
is the number and appearance chromosomes in the nucleus of a eaukaryotic cell
KARYOTYPE
Once the cells have been obtained for a karyotype, they are mixed with plant-derived chemicals
Stimulate mitosis
LECTINS
After the required quantity of cell has been acquired, the cells are treated with a drug
Colchicine
cell are place that causes them to take on water, thereby increasing their overall size
Hypotonic solution
How the chromosomes may be distinguished from one another based upon several characteristics
i. the length of the arm of the chromosome
ii. shape
iii. general appearance of the chromosome
a chromosome number that is a multiple of the normal haploid set
Polyphloidy
a chromosomal number that varies by something less that a set
Aneuphloidy
having only one member of a homologous pair
Monosomy
having three copies of a single chromosomes
TRISOMY
______________ percentage of early embryonic deaths and spontaneous abortions are caused by aneuploidy
35% - 70%
_____________ percentage of early childhood deathstare related to aneuploidy
5% - 7%
Caused by errors in meiosis, events after fertilization, errors in mitosis
Polyploidy
Three set of chromosome, most common form of polyploidy, 15% - 18% of all spontaneous abortions
Triploidy
Four sets of chromosomes, 5% of all spontaneous abortions, extremely uncommon in live births, may result from failure pf cytokinesis in the first mitotic division, life threatening
Tetraploidy
i.
Lethal condition
ii.
Aneuploidy during gamete formation produces equal numbers of monosomic and trisomic gametes and embryos.
iii.Rarely seen in spontaneous abortions and live births
iv.Majority are lost early in development
Autosomal Monosomy
i.1/10,000 births
ii.Average survival time: 2-4 months
iii. Edward Syndrome [47, +18]
Trisomy 18
i.1/5,000births
ii.Lethal: mean survival time is at least 1 month
iii.Patau Syndrome [47, +13]
Trisomy 13
-1/700 live births
-40% congenital heart defects.
-down syndrome [47, +21]
Trisomy 21: Down Syndrome (47, +21)
i.Advanced maternal age
ii.Risk increases rapidly after 35 years of age
Risk for Autosomal Trisomy
• 1/1000
• male/mental dysfunction
Klinefelter’s Syndrome (47, XXY)
• 1/5000births
• female/ no mental dysfunction
• Single Xchromosome
Turner Syndrome (45, X)
•1/1000births
•Above average in height
• antisocial behavior
Jacob Syndrome (47, XYY)
-most lethal
-50% cases of chromosomal abnormalities that cause fetal death
-rish increase after 35 yrs of age
Autosomal Trisomy
