1. Karyotype Chromosome Abnormalities Pedigree
Human Genetics
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
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 (= ____________)
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 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.