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. Who determines the Sex of offspring in Humans?

7. Sex-Limited, Influenced Traits and Sex Linked
Some traits are carried on the sex chromosomes =
X and Y
Most Traits are on X
Y is smaller, so few genes located.

8. Sex-Limited Traits
Genes inherited by both male and female but expressed only in one sex due to SEX HORMONES
EX: Beards, breasts, antlers, milk production, feathers on bird

9. Sex-Influenced Traits
Autosomal genes influenced by sex.
Genes DOMINATE in one sex and RECESSIVE in other
Males and females with the same genotype will have different phenoypes
EX: Index vs Ring finger
Short index finger: Dom. in Males
Rec. in Females
(FYI: Shorter man’s index finger,
the higher amt of prenatal testosterone
(corresponds to physically aggressive behavior)

10. Sex-Influenced Traits
Examples Continued:
Hairlip and Gout
Dominant in males
Recessive in females
Spina Bifida:
Dom. in females
Rec. in Males

11. Sex-Influenced Traits
Other Examples:
Baldness:
Dom. In Males
Rec. in Females
B=baldness, B’=normal hair
BB=bald (male/female)
B’B’=normal hair (male/female)
BB’= bald (male) normal (female

12. The Adams family

13. Sex Linkage Controlled by GENES on SEX CHROMOSOMES.
X chromosome is larger than y  more genes carried on the X
X-Linked Genes: genes found on X chromosome
Appear mostly in males
Only one copy of X; nothing to counteract “bad gene”
Females would need two copies to express trait

14. Traits on X Chromosome Red-Green Color Blindness (XR Xr Y°)
Hemophilia (inability of blood to clot)
XH-normal XHY° XhY°-hemo
Muscular Dystrophy (I muscles)

16. 4) 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

17. normal
vision
“weak red”
“weak green”

18. XN Y XN Xn XNXN XNY XN Xn XnY Cross of carrier female & normal male
Phenotypes???

19. Hemophilia X-linked recessive Most Common in males “Bleeder’s Disease”
Missing clotting factor
Bleeding spontaneously and in joints

20. Xh Y XH Xh XHY XHXh Xh Xh XhY Hemophilia
Hemophila is sex-linked recessive trait.
Normal clotting is dominant.
Hemophiliac Male X Carrier (Heter.) Female
LET: XH normal
Xh hemo
YO no trait Xh Y XH
XHY
XHXh Xh
Xh Xh
XhY

21. Carrier Mom
XHXh
XHXH XHXh XHY XhY

22. Royal Hemophilia

25. Sex linkage & calico cats

26. Traits on Y CHROMOSOMES
Ex. Long Hair on Earlobes
3 Muslim brothers from South India.

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

28. nondisjunction

29. Trisomy 21

31. Klinefelter’s syndrome

32. Klinefelter’s

34. Super male
Super male

35. 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

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

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

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

40. Polydactyly (multiple fingers and toes)