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Karyotype Chromosome Abnormalities Pedigree

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Presentation on theme: "Karyotype Chromosome Abnormalities Pedigree"— Presentation transcript:

1 Karyotype Chromosome Abnormalities Pedigree
Human Genetics Karyotype Chromosome Abnormalities Pedigree

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

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 Karyotype

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 Figure 13.3 Preparing a karyotype 6


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
CHROMOSOMAL 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

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

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

12 Nondisjunction

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

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

15 Down syndrome (= ____________)

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 years chromosomes more likely to “stick”

20 Turner syndrome

21 Turner syndrome ____ XO 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

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

25 Human Genetics 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

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

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

28 Pedigree Analysis Symbols

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


31 http://www. ikm. jmu. edu/Buttsjl/ISAT493/Hemophilia/hemophiliaeurope

32 Pedigree Analysis Inferring Genotypes Predicting Disorders
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.

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