Unit 4--Genetics

1
Unit 4--Genetics

• Chapter 14
• Human Heredity

2

• 1) Autosomes
• 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

4
(No Transcript)
5
(No Transcript)
6

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

7

• Turners syndrome

Only 1 sex chromosome is present. Turner syndrome
is associated with underdeveloped ovaries, short
stature, webbed neck, and broad chest.
Individuals are sterile, and lack expected
secondary sexual characteristics. Mental
retardation typically not evident .
XX
XX
O
8

• Klinefelters syndrome

9

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

10

• 6) Blood groups

of U.S. population
11
Serum
Universal recipient
Universal donor
12

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

13
Normal, with malarial resistance
Same as parents normal, no
resistance sickle-cell anemia
14

• 8) 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

15
normal vision
weak red
weak green
16
Cross of carrier female normal male



XN
Xn
XN
XNXN
XNXn
Y
XNY
XnY
Phenotypes???
17
Carrier Mom
XHXh
XHXH XHXh XHY XhY
18
Royal Hemophilia
19
Sex linkage calico cats
20
Polydactyly(multiple fingers and toes)