Presentation on theme: "Section 7-2 “Complex Inheritance”"— Presentation transcript:
1Section 7-2 “Complex Inheritance” Write everything that is BLACK
2KEY CONCEPT Phenotype is affected by many different factors
3Phenotype can depend on interactions of alleles Incomplete dominance: neither allele is completely dominant nor completely recessiveHeterozygous phenotype is intermediate between the two homozygous phenotypes
4Codominant 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
5How 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.
6Many genes may interact to produce one trait Polygenic traits are produced by two or more genesOrder of dominance: brown > green > blue.
7An epistatic gene can interfere with other genes An epistatic gene blocks the production of pigments.
8How 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
9The 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
10Sunlight 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.