Presentation on theme: "KEY CONCEPT Phenotype is affected by many different factors."— Presentation transcript:
1KEY CONCEPT Phenotype is affected by many different factors.
2Phenotype 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”
3List 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
4List 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
5Codominance 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
6Blood 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.
7B 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
8B 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
9Many genes may interact to produce one trait. Polygenic traits are produced by two or more genes.Order of dominance: brown > green > blue.
10An epistatic gene can interfere with other genes. This is like a “knock out” gene
11The 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.