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

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

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

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%

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

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

INCOMPLETE DOMINANCE

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

Codominance-Coco the spotted chicken

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

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-

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

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

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