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Karyotype Chromosome Abnormalities Pedigree. A __________ is a picture of an organism’s chromosomes KARYOTYPE.

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Presentation on theme: "Karyotype Chromosome Abnormalities Pedigree. A __________ is a picture of an organism’s chromosomes KARYOTYPE."— Presentation transcript:

1 Karyotype Chromosome Abnormalities Pedigree

2 A __________ is a picture of an organism’s chromosomes KARYOTYPE

3 Chromosomes that determine the sex of an organism = _________________ All other chromosomes = _________________ Sex chromosomes autosomes Humans have two sex chromosomes and _____ autosomes X y 44

4 Karyotype Karyotype- an organized profile of a person’s chromosomes  Chromosome are arranged and numbered by size, from largest to smallest  The two chromosomes in each pair are called homologous chromosomes or homologs

5 Creating a Karyotype Scientists take a picture of someone’s chromosomes, cut them out, and match them up using:  Size  Banding pattern  Centromere position as guides

6 Fig. 13-3a APPLICATION


8 Why create a Karyotype? Determine abnormalities or defective chromosomes that could possibly be passed to offspring Help determine proper treatment for some types of cancer Identify the sex of a person, if unclear at birth

9 ________________ Abnormalities 1 infant in 200 newborns has a chromosomal abnormality 28% of first trimester miscarriages have a chromosomal abnormality Abnormalities in larger chromosomes don’t usually survive CHROMOSOMAL

10 ____________________________: Change in the ______________ or ____________ of chromosomes CHROMOSOMAL MUTATIONS structure number

11 Homologous chromosomes ________________ during MEIOSIS = _________________________ One cell gets 2 copies of the chromosome the other cell gets none. NONDISJUNCTION fail to separate

12 Nondisjunction

13 Since it happens to a sperm or egg, the new baby can end up with _____________ of a chromosome = __________________ OR only ___________ of a chromosome = ___________________ TRISOMY MONOSOMY 3 copies one copy

14 Human Abnormalities caused by Non-Disjunction __________________ __________________ __________________ Down syndrome Klinefelter syndrome Turner syndrome

15 Down syndrome (= ____________) TRISOMY 21

16 Down syndrome (Trisomy 21) 1 in 800 births Similar facial features Slanted eyes Protruding tongue

17 Down syndrome (Trisomy 21) Simian line on palm

18 Down syndrome (Trisomy 21) Most common chromosomal abnormality 50% have heart defects that need surgery to repair Mild to severe mental retardation Increases susceptibility to many diseases Risk of having a child with Down syndrome increases with age of mom

19 Down syndrome (Trisomy 21) Risk of having a child with Down syndrome related to age of mom More common in women UNDER 16 or OVER 35 Cells that make eggs start meiosis in embryo Stop in PROPHASE I (synapsis) One egg restarts & finishs division each month So an egg released at age 40 has been in synapsis for 40 years... chromosomes more likely to “stick”

20 Turner syndrome

21 Turner syndrome ____ 1 in 5000 births Females have only one X chromosome Small size Slightly decreased intelligence 35% have heart abnormalities Hearing loss common Broad chest Reproductive organs don’t develop at puberty Can’t have children XO

22 Klinefelter syndrome XXy

23 Klinefelter syndrome 1 in 1000 births Males have extra X chromosomes (Can be XXy, XXXy, or XXXXy) Average to slight decrease in intelligence Small testes/can’t have children Usually not discovered until puberty when don’t mature like peers

24 Karyotype ( need cells from baby) Can tell __________________ chromosomes __________ Some _____________________ Can’t see _______________ mutations Image from: MISSING/EXTRA GENDER DELETIONS/INSERTIONS single gene

25 Difficulties with human genetics:  Takes a long time to reach reproductive maturity  Relatively few offspring  Unethical to “arrange” matings between individuals with desired genotypes  Pedigree – a graphic representation of genetic inheritance, a families phenotypic history  Made up of set of symbols Human Genetics

26 _______________are diagrams that show how are ____________ on __________ over several generations PEDIGREES genes are passed in families

27 A __________ person who carries a _________ allele for a genetic disorder, but ______________ the disorder themselves is called a _____________ CARRIER heterozygous doesn’t show recessive

28 Pedigree Analysis Symbols

29 Pedigree Analysis Family Trees  Generations are numbered on the left with roman numerals  Siblings are numbered in birth order



32 Complex Inheritance and Human Heredity Inferring Genotypes  Knowing physical traits can determine what genes an individual is most likely to have. Predicting Disorders  Record keeping helps scientists use pedigree analysis to study inheritance patterns, determine phenotypes, and ascertain genotypes. Pedigree Analysis

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