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