Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the...
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![Page 1: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/1.jpg)
Karyotypes and NondisjunctionKaryotypes and Nondisjunction
April 2, 2009April 2, 2009
![Page 2: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/2.jpg)
Some inherited traits can be identified at the chromosome level.
Geneticists use karyotypes.Chromosomes are stained.A photomicrograph is taken of a cell’s
chromosomes during metaphase.Chromosomes pairs are arranged in order of
decreasing size.
![Page 3: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/3.jpg)
![Page 4: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/4.jpg)
Test Benefit Risk
Amniocentesis• Diagnosis of chromosome abnormalities• Diagnosis of other defects
• Discomfort for expectant mother
• Slight risk of infection• Risk of miscarriage
Chorionic villus sampling
• Diagnosis of chromosome abnormality• Diagnosis of certain genetic defects
•Risk of miscarriage•Risk of infection•Risk of newborn limb defects
Fetal blood sampling
• Diagnosis of genetic or chromosome abnormality
• Checks for fetal blood problems and oxygen levels
• Medications can be given to the fetus before birth
• Risk of bleeding from sample site
• Risk of infection• Amniotic fluid might leak• Risk of fetal death
Amniocentesis procedure
![Page 5: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/5.jpg)
Cell division in which either the homologous pairs or sister chromatids do not separate correctly, resulting in gametes with an abnormal number of chromosomes.
![Page 6: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/6.jpg)
Monosomy – having only one of a particular type of chromosome.Trisomy – having a set of three chromosomes of one kind
e.g. Down syndrome (Trisomy 21)Results in distinctive facial features, short stature, heart defects, and mental disability
![Page 7: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/7.jpg)
Females can survive with only one X chromosome or with three. Males can survive with either an extra X or an extra Y. Males cannot survive with only a Y chromosome.
Genotype
XO XXX XXY XYY OY
Phenotype
Female with Turner’s
syndrome (sterile)
Nearly normal female
Male with Klinefelter’s syndrome (sterile)
Normal or nearly normal
male
Results in death
![Page 8: Karyotypes and Nondisjunction April 2, 2009. Some inherited traits can be identified at the chromosome level. Geneticists use karyotypes. Chromosomes.](https://reader036.fdocuments.us/reader036/viewer/2022062801/56649e585503460f94b51135/html5/thumbnails/8.jpg)
Biggs, Haggins, Holliday. Biology (Glencoe Science)(Teacher Wraparound Edition). New York: GLENCOE MCGRAW HILL, 2007.
Farabee, M. J. Human Genetics. 2001. 01 Apr. 2009 <http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookhumgen.html>.
Downschild. Digital image. About Downs Syndrome. 2008. The Coventry and Rugby Down's Syndrome Support Group. 01 Apr. 2009 <http://www.downssupport.org.uk/aboutdowns.html>.
"Genetics and pregnancy loss." Miscarriage Management™ -. 2009. Sydney IVF Limited. 01 Apr. 2009 <http://www.miscarriage.com.au/basepage.cfm?id=16>.
Karyotype. Digital image. AP Biology. 01 Apr. 2009 <http://www.nkellogg.com/apbiology.htm>.
Nondisjunction. Digital image. 01 Apr. 2009 <http://porpax.bio.miami.edu/~cmallery/150/mendel/heredity.htm>.