DNA, Genes, Chromosomes, and Cells. Your body is made of trillions of cells, each one with a...
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Transcript of DNA, Genes, Chromosomes, and Cells. Your body is made of trillions of cells, each one with a...
DNA, Genes, Chromosomes, and Cells
• Your body is made of trillions of cells, each one with a nucleus.
• Inside each nucleus are 46 chromosomes.
You got 23 from mom, 23 from dad
• Chromosomes are made of many genes
http://www.connectmydna.com/the-science/
• Genes are made of long sections of DNA (deoxyribonucleic acid)
DNA
http://abcnews.go.com/blogs/business/2013/04/letter-on-dna-structure-sells-for-record-5-3-million/
• Some of the genes you inherit are dominant, some of the them are recessive.
• Scientists can look at these genes on your chromosomes and use them to help diagnose disease or provide better treatment.
http://cpmc.coriell.org/
You may soon go to your doctor with a picture of your chromosomes
Karyotype
Normal babies have cells with 46 chromosomes
Normal sperm and egg cells each have 23 chromosomes
A picture of a cell’s chromosomes is called a karyotype.
Chromosomes are paired up and lined up according to their patterns
and size.
We use “cartoon” versions of chromosomes to make our task
easier.
The different patterns on
chromosomes are different
genes for traits
A karyotype can be used to diagnose a disease or determine
gender
Boys are XY, girls are XX for chromosome #23
Sometimes there are extra or missing chromosomes
Turner’s Syndrome (one X)
Klinefelter’s Syndrome (XXY)
Cri du Chat Syndrome (deleted part of chromosome 5)
Down Syndrome (3 copies of #21)
Karyotypes can be made for a fully formed human or for a developing
fetus.
Why would a parent want to know a child’s karyotype?
Early testing can help parents prepare physically and
emotionally for the birth of their child. They can be better
prepared to meet the needs of their child with early
intervention and care.
To determine risk of a genetic disorder or the gender of the child.
Even plants can have a karyotype made of their chromosomes for
identification purposes
Genetic testing can now be used to search for potential diseases
• Breast/ovarian cancer (#17 and 13)
• Alzheimer’s (#19)
• Cystic Fibrosis (#7)
• Autism (#15 is different if the person has this disease-not yet known why this happens)
Genetic testing can also be used to determine gender, especially in
cases of elite athletes.
http://www.hhmi.org/biointeractive/gendertest/gendertest.html
http://www.nytimes.com/2010/04/08/sports/08sportsbriefs-semenya.html
http://news.bbc.co.uk/2/hi/programmes/newsnight/9373209.stm
Your task:
• You will receive a sample of chromosomes from a developing fetus.
• You must arrange the chromosomes according to size and pattern into a karyotype.
• You will then determine the gender and disease this child may have (if any).
• Conclusion questions and karyotype are due on Thursday.
Instructions:1. Carefully cut apart the chromosomes, do NOT lose any!
2. Using the “Normal Karyotype” as your guide, arrange the patient’s chromosomes according to the same pattern.
3. Glue/Tape the chromosomes into place on the attached paper.4. Compare your patient’s karyotype to the normal karyotype and the disease
chart to determine, what disease, if any, the child has.
Genetic DisorderDown's Syndrome Turner's Syndrome Klinefelter Syndrome Cri du Chat Syndrome
karyotype change 3 copies of chromosome 21
one X only for chromosome 23
XXY for chromosome 23 deleted part of chromosome 5
How often does it occur? 1 in 800 1 in 2000 1 in 750 1 in 50,000
Physical Symptoms
mental retardation, eyes slant upwards, prone to heart defects and respiratory problems.
normal female in childhood, normal intelligence, fails to fully undergo
puberty and will remain infertile
male, normal in appearance and intelligence, sterile, may show some female characteristics (breast development, feminine
body shape)
distinctive cat-like cry in babies, respiratory
problems, shortened life
span is possible
Genetic DisorderTriple X Syndrome Edward's Syndrome Patau Syndrome Trisomy 23
karyotype change XXX for chromosome 23 3 copies of chromosome 18 3 copies of chromosome 13 XYY for chromosome 23
How often does it occur? 1 in 700 1 in 6,000 1 in 15,000 1 in 2,000
Physical Symptoms
female with normal intelligence and
appearance, may be sterile
feeding and breathing difficulties,
developmental delays, deformation of head
and face, cardiac defects, often results
in early death
mental retardation, cleft palate, extra fingers and
toes, incomplete development of internal organs, often results in
early death
male with low mental ability, normal in
appearance
Genetic Disorder Down Syndrome
karyotype change
3 copies of chromosome 21
How often does it occur?
1 in 800
Physical Symptoms
mental retardation, eyes slant upwards, prone to heart defects and respiratory problems.
http://www.ndss.org/
Genetic disorder
Turner Syndrome
karyotype change
one X only for chromosome 23
How often does it occur?
1 in 2000
Physical Symptoms
normal female in childhood,
normal intelligence, fails to fully
undergo puberty and will remain infertile
http://www.turnersyndrome.org/welcome-turner-syndrome-society-us
Genetic disorder
Klinefelter Syndrome
karyotype change
XXY for chromosome 23
How often does it occur?
1 in 750
Physical Symptoms
male, normal in appearance and
intelligence, sterile, may show
some female characteristics
(breast development, feminine body
shape)
http://ghr.nlm.nih.gov/condition/klinefelter-syndrome
Genetic disorder
Cri du Chat Syndrome
karyotype change
deleted part of chromosome 5
How often does it occur?
1 in 50,000
Physical Symptoms
distinctive cat-like cry in babies,
respiratory problems,
shortened life span is possible
http://www.fivepminus.org/
Genetic disorder
Triple X Syndrome
karyotype change
XXX for chromosome 23
How often does it occur?
1 in 700
Physical Symptoms
female with normal
intelligence and appearance,
may be sterile http://www.mayoclinic.com/health/triple-x-syndrome/DS01090
Genetic disorder
Edwards Syndrome
karyotype change
3 copies of chromosome 18
How often does it occur?
1 in 6,000
Physical Symptoms
feeding and breathing difficulties,
developmental delays,
deformation of head and face, cardiac defects, often results in
early death (fewer than 10% live for a
year)
http://www.trisomy18.org/site/PageServer?pagename=parents_whatisT18
Genetic Disorder
Patau Syndrome
karyotype change
3 copies of chromosome 13
How often does it occur?
1 in 15,000
Physical Symptoms
mental retardation, cleft
palate, extra fingers and toes,
incomplete development of internal organs, often results in
early death http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002625/
Genetic Disorder
Trisomy 23
karyotype change
XYY for chromosome 23
How often does it occur?
1 in 2,000
Physical Symptoms
male with low mental ability,
normal in appearance
http://ghr.nlm.nih.gov/condition/47xyy-syndrome