 Trait: a specific characteristic (color, hair, etc.)  Heterozygous: two different alleles; one dominant, one recessive  Homozygous: two alleles that are the same; homozygous dominant or recessive  Hybrid: offspring of crosses between parents with different traits  Incomplete Dominance: when an allele isn’t completely dominant over another  Codominance: when both alleles are seen

 Even with purebred dogs, incomplete dominance is shown, as seen in the next slide, when one trait, in this case color, isn’t completely dominant.

 If a dog isn’t a purebred it’s a hybrid. A Shih-tzu bred with a Yorkie will produce Shorkies, a hybrid. Also, a Poodle and a Yorkie will give you a Yorkie Poo.

 Looking at hybrids, we can see codominance. Both parents’ genes can be seen. Hair: She has coarse hair that doesn’t have to be groomed very often Ears: She has Chihuahua ears that stick up when she’s excited Face: She has the poodle face, with a long-ish nose and large eyes Body: She has the poodle build

Face: Her face has a “squished in” appearance, which is the Shih Tzu face Tail: Her tail curves up, like the Shih Tzu Build: She has the stocky, short Shih Tzu build Hair: She has fluffy hair, like a Pomeranian Ears: Her ears are floppy and large, like Pomeranians

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 All pictures: Dogz by Design   If you ever want to buy small house dog, let us know!  Prentice Hall: Biology science book  der-talk/ recessive-yorkie.html  html