Transcript Karyotypes - Cloudfront.net

Pick up warm-up from front table.
Complete warm-up first!
 When finished…get out sponge bob
worksheet. Do you have any questions???
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
You will need a RING today.
Projects are due Thursday
 Genetics Unit Test is Friday
 I will be here after school Wed & Thur
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Karyotypes
What are they??
How do we use them?
Normal Karyotype--male
Normal Karyotype--female
Is this person female or male?
Hold up a red or blue card on your ring.
How are DNA samples obtained for
karyotypes?
Amniocentesis: obtaining amniotic
fluid which has cells from the fetus
Chorionic villi sampling: removing
cells from the chorion with fetal tissue
What to look for?
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Are there 46 chromosomes?
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Are there 2 identical pairs of each
autosome and 2 sex chromosomes?
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Are there any rearrangements between
chromosomes or large deletions?
Trisomy 21 or Down Syndrome
1 in 700 births
47 chromosomes
XY or XX
#21 Trisomy
Nondisjunction
3
Correlation between mother’s age
and Trisomy 21 incidence
Turners syndrome
caused by
Nondisjunction
Monosomy
Male or Female? Show red or blue card on ring.
Is this a normal karyotype??
XXY Male (Extra X)
Klinefelter syndrome
XXY on 23rd pair
 Male with some female characteristics
 small testes that do not produce as much
testosterone as usual
 Delayed puberty
 Reduced body hair
 infertility
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Deletion—18 Q Deletion Syndrome
If there are chromosomal number
abnormalities, how do they form?
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Meiosis: the process of creating sperm or
egg from a diploid cell
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If there is a mistake when chromosomes
are separating, then the resulting sperm
or egg will have too many or too few
chromosomes.
Nondisjunction
What we can’t see
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Individual DNA strands or genes
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The number of genes in any given area of
a chromosome.
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The presence or location of small
mutations. (Scientists cannot predict
diseases caused by small mutations within
genes.
Other chromosomal
disorders that can
arise?
Problems with chromosomes
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Duplication: copied parts of chromosome
A
A
B
B
C
B
D
B
C
D
Problems with chromosomes
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Deletion: missing parts of chromosome
A
A
B
D
C
D
Problems with chromosomes
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Inversion: parts of chromosome tched
A
A
B
C
C
B
D
D
Chromosomal mutations
Deletion
Duplication
Inversion
Translocation
Human genetic disorders from
deleterious genes
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Sometimes the alleles inherited contribute to
disorders and not from the number or shape of
the chromosomes.
Sex-linked: genes found on X or Y
chromosome
2. Recessive: requires 2 allele copies to express
disorder
3. Dominant: requires only 1 allele copy to
express disorder
1.
Recessive disorders
Dominant disorder
Mile-a-minute
Sex Chromosomes
Trisomy
Kleinfelter’s Syndrome
Insertion
Nondisjunction
Mile-a-minute
Monosomy
Down Syndrome
Karyotype
Inversion
Nondisjunction in Meiosis I
Mile-a-minute
Deletion
Turner’s Syndrome
Nondisjunction in Meiosis II
Autosome
Sex-linked trait
Mile-a-minute
Incomplete dominance
Carrier
Pedigree
Codominance
Heredity