Presentation on theme: "Section 7-2 “Complex Inheritance”"— Presentation transcript:
1 Section 7-2 “Complex Inheritance” Write everything that is BLACK
2 KEY CONCEPT Phenotype is affected by many different factors
3 Phenotype can depend on interactions of alleles Incomplete dominance: neither allele is completely dominant nor completely recessiveHeterozygous phenotype is intermediate between the two homozygous phenotypes
4 Codominant alleles will both be completely expressed Codominant alleles are neither dominant nor recessiveThe ABO blood types result from codominant allelesMany genes have more than two alleles
5 How can two people with type B blood have a child with type O blood? If two people are heterozygotes (IBi) they can each pass the recessive allele (i) to their offspring.
6 Many genes may interact to produce one trait Polygenic traits are produced by two or more genesOrder of dominance: brown > green > blue.
7 An epistatic gene can interfere with other genes An epistatic gene blocks the production of pigments.
8 How do multiple allele traits differ from polygenic traits? Multiple allele traits are influenced by several different versions of one gene; polygenic traits are influenced by multiple genes
9 The environment interacts with genotype Phenotype is a combination of genotype and environmentThe sex of sea turtles depends on both genes and the environmentHeight is an example of a phenotype strongly affected by the environmentWarm = femaleCold = Male
10 Sunlight can cause a person’s hair to become lighter in color Sunlight can cause a person’s hair to become lighter in color. Is this an example of an interaction between genes and the environment? Why or why not?Yes, because the phenotype is altered by the environment.