1. MORE GENETICS VOCABULARY & EXAMPLES
Multiple Alleles
Incomplete Dominance
Co dominance
Sex-linked

2. Multiple Alleles A. Human Blood Groups 1. ABO Blood Groups
a. Type A: A antigen, IA IA or IA i
b. Type B: B antigen, IB IB or IB i

3. c. Type AB: both A&B antigens, IA IB
d. Type O: no antigens, ii

4. How common are the blood types?
AB+ O- A- B-
AB-
37.4%
35.7%
8.5%
3.4%
6.6%
6.3%
1.5%
0.6%

5. Incomplete Dominance Heterozygous has a “blended” look
Neither allele covers or hides the other
Mix

6. Alleles are mixed.
For example, red cows crossed with white will create roan (orange) cows.

7. INCOMPLETE DOMINANCE

8. Co Dominance Both alleles are expressed Can look checkered or spotted
Appaloosa horses, speckled chickens, Sickle Cell Anemia

9. Codominance-Coco the spotted chicken

10. Sex Linked Traits Hemophilia Muscular Dystrophy Color Blindness
Found on X chromosome
More than 100 sex-linked genetic disorders
The Y chromosome is much smaller than the X chromosome and appears to have only a few genes.
Hemophilia
Muscular Dystrophy
Color Blindness

11. Color Blind XCXC XCY X- XC X-Y XC Y X- Father XCY Daughter
(Normal Vision)
XCY
Son X-
X- XC
(Carrier)
X-Y
(colorblind)
Mother
XCX-

12. Polygenic Traits POLYGENIC TRAIT (POLY=MANY)
EYE COLOR & SKIN COLOR ARE TRAITS CONTROLLED BY MANY GENES.

13. PEDIGREE
CHART THAT SHOWS HOW A TRAIT IS INHERITED WITHIN A FAMILY

14. CONT.
WHEN A PERSON HAS THE RECESSIVE GENE THAT CAUSES A DISEASE BUT IS NOT AFFECTED BY IT, THEY ARE CALLED A
CARRIER (Tt)