| A | B |
|---|
| hair color | human trait in which brown is dominant over blond; blond is recessive to brown, but it is dominant over red; red is recessive to all non-red colors |
| eye color | human trait in which brown is dominant over blue; blue is recessive to brown |
| tongue-rolling | this is a dominant trait while the inability to do this is recessive |
| color of "four o'clock flowers" | an example of incomplete dominance (in which red crossed with white results in pink) |
| skin color in humans | an example of incomplete dominance (in which a very dark Negro crossed with a very light Caucasian results in a warm brown color called "mulatto") |
| blood type in humans | a trait determined by multiple alleles, where some are dominant and some are recessive(A with O, B with O), but others show incomplete dominance (A with B) |
| baldness | sex-linked trait affecting men in their 20's or later in their lives |
| hemophilia | sex-linked trait affecting men and boys and the ability to clot their blood when there is injury or surgery |
| colorblindness | sex-linked trait affecting mainly males and their ability to see differences between certain colors |
| Down Syndrome | three chromosomes instead of two on Pair #21 (sometimes called Trisomy 21 or mongolism) |
| albinism | a recessive trait that is a chromosome mutation resulting in an inability to produce pigment in the skin, hair and eyes; normal pigment is dominant |
| the child's father | the parent who determines the sex of a baby |
| the child's mother | the parent who passed the hemophilia gene on to their hemophiliac son |
| XX | the two sex chromosomes that make a human a female |
| XY | the two sex chromosomes that make a human a male |
| 46 (23 pairs) | the number of chromosomes in any normal human body cell |
| 23 | the number of chromosomes in a normal human sex cell (egg cell or sperm cell) |
| XcXc | genotype for a colorblind female |
| XcY | genotype for a colorblind male |
| XCXc | genotype for a non-colorblind female who is a carrier |
| XCY | genotype for a non-colorblind male |
| AA | pure genotype for Type A blood |
| Ao | hybrid genotype for Type A blood |
| AB | genotype for Type AB blood |
| oo | genotype for Type O blood |
| BB | pure genotype for Type B blood |
| Bo | hybrid genotype for Type B blood |
| RR | genotype for red four o'clock flowers |
| WW | genotype for white four o'clock flowers |
| RW | genotype for pink four o'clock flowers |
| Bb | hybrid genotype for brown hair |
| BB | pure genotype for brown hair |
| bb | genotype for blond hair (which is recessive to brown) |
