Patterns of Inheritance

Vocabulary

• Incomplete dominance: 1 allele only partially dominant

• Co-dominance: both alleles for genes exposed equally

• Multiple alleles: 3 or more possible alleles determine trait

• Polygenetic inheritance: more than 1 gene effects trait

Incomplete dominance• Red snapdragons crossed with white• Pink snapdragons• Two white- WW• RR- red• Capital letters- neither totally dominant• RW- only a little red, a little white• Appear pink

Co-dominance

• Neither allele dominant• Black, white chickens• All chickens have black, white

feathers• FB- black feathers• FW- white feathers• F- fathers• Superscripts- tells you color

feathers

Multiple Alleles• 3 or more possible alleles determine trait• Rabbits coat color ranges brownish gray- all white• Depends on alleles inherited• Leads to differences among siblings

Polygenetic inheritance• Alleles different genes work together produce trait• Broad range phenotypes• Human height• Plant flowering time

Acquired Traits• Inherited

-Vocal cords

-Height

-Hair color• Acquired

-speak languages

-callus on finger- writing

-haircut

Genes and environment• Environmental factors influence way genes expressed• Tobacco smoke• Pollutants- result in cancer• Changes body cells not passed to offspring• Changes in sex cell• Egg, sperm passed to offspring