Presentation on theme: "KEY CONCEPT Phenotype is affected by many different factors."— Presentation transcript:
1 KEY CONCEPT Phenotype is affected by many different factors.
2 Phenotype can depend on interactions of alleles. In incomplete dominance, neither allele is completely dominant nor completely recessive.Heterozygous phenotype is intermediate between the two homozygous phenotypesHeterozygous is like a “blend”
3 List the genotypes. 4RW List the phenotypes. 4 Pink W W R W R W R pink Example: Cross a homozygous red carnation flower (RR) with a homozygous white flower (WW).List the genotypes.4RWList the phenotypes.4 PinkW WRWRWRpinkpinkRWRWpinkpink
4 List the genotypes. 2RW, 2WW List the phenotypes. 2 Pink, 2White R W R Example: Cross one heterozygous pink (RW) 4 o’clock flower with a White flower (WW).List the genotypes.2RW, 2WWList the phenotypes.2 Pink, 2WhiteR WRWWWWpinkwhiteRWWWpinkwhite
5 Codominance red white roan Defined: When both alleles are dominant and equally expressedThe colors do NOT blend together, but are equally seenEx: Cattle CoatRed cow x White cow =Roan CowEx: Human Blood typesType A x Type B = Type ABredwhiteroan
6 Blood types are another example of codominance. The ABO blood types result from codominant allelesThis blood group consists of 3 different allelesDominant A alleleDominant B alleleRecessive O alleleA and B are equallydominantMany genes have more than two alleles.
7 B B A A B A B A B A B List the genotypes. 4AB List the phenotypes. Ex: Cross Jason who is homozygous for type A blood with Maria who is homozygous for type B blood.List the genotypes.4ABList the phenotypes.4 type AB bloodB BAABABABAB
8 B o A o A B A o B o o o List the genotypes. 1AB, 1Ao, 1Bo, 1oo Ex: Cross Mike who is heterozygous for type A blood with Lisa who is heterozygous for type B blood.List the genotypes.1AB, 1Ao, 1Bo, 1ooList the phenotypes.1 type AB blood1 type A blood1 type B blood1 type o bloodProbability of Heterozygous individual?75%B oAoABAoBooo
9 Many genes may interact to produce one trait. Polygenic traits are produced by two or more genes.Order of dominance: brown > green > blue.
10 An epistatic gene can interfere with other genes. This is like a “knock out” gene
11 The environment interacts with genotype. Phenotype is a combination of genotype and environment.The sex of sea turtles depends on both genes and the environmentHeight is an example of a phenotype strongly affected by the environment.