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Human Heredity.

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Presentation on theme: "Human Heredity."— Presentation transcript:

1 Human Heredity

2 1) Autosomes 2) Sex chromosomes
all the chromosomes except the sex chromosomes (in humans, there are 22 pair) 2) Sex chromosomes The sex-determining chromosomes, the X & Y

3 3) Karyotype Pictures of paired human chromosomes arranged by size, used to identify abnormalities in fetuses Cells from an amniotic fluid sample are cultured, stained & photographed



6 4) Nondisjunction Failure of chromosomes to separate
May cause a variety of birth defects, including trisomy 21 or Down syndrome

7 Turner’s syndrome XX XX O Only 1 sex chromosome is present.
*Associated with underdeveloped ovaries, short stature, webbed neck, and broad chest. *Individuals are sterile, and lack secondary sexual characteristics. *Mental retardation typically not evident . XX XX O

8 Klinefelter’s syndrome

9 5) Pedigree Chart showing family history of a trait
Solid light = homozygous dominant, solid dark = homozygous recessive, half-circle = heterozygous

10 6) Genetic disorders Harmful effects produced by mutated genes, most are recessive and few are lethal Example: sickle cell anemia

11 Normal, with malarial resistance
Same as parents ; normal, no resistance; sickle-cell anemia

12 7) Sex-linked traits A recessive gene on the X chromosome
Examples: color-blindness & hemophilia Genotypes: Phenotypes: XNY normal male XnY colorblind XNXN normal female XNXn carrier female XnXn colorblind

13 normal vision “weak red” “weak green”

14 XN Y XN Xn XNXN XNY XN Xn XnY Cross of carrier female & normal male

15 Carrier Mom XHXh XHXH XHXh XHY XhY

16 Royal Hemophilia

17 Sex linkage & calico cats

18 Polydactyly (multiple fingers and toes)

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