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Complex inheritance.

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Presentation on theme: "Complex inheritance."— Presentation transcript:

1 Complex inheritance

2 Complex inheritance and Expression
Phenotype can depend on interactions of alleles. Traits can rely on a wide range of dominance. Phenotype can also be influenced by environment Turtle eggs that are held at warmer temperatures tend to turn into female turtles.

3 Incomplete dominance Incomplete dominance is when the heterozygous is a blending of traits. Example: When a red flower and a white flower have a pink baby.

4 Incomplete dominance

5 Codominance Codominance is when both alleles are expressed equally in the heterozygous. Neither allele is dominant or recessive. Example: Example: When a red flower and a white flower have a red and white spotted baby.

6 Codominance

7 Polygenic traits A polygenic trait is when many genes interact to produce 1 trait. Human skin color and eye color are examples of polygenic traits. (Look at figure 7.7 on pg. 206).

8 Epistasis An epistatic gene is one that interferes with the expression of others. For example albinism is caused when an epistatic gene blocks the genes that produce pigment.

9 Pedigrees A pedigree uses a chart that can trace the phenotypes and genotypes within a family. They are a useful tool in checking a family's history for genetic disorder or disposition.

10 pedigree The symbols: -Square=male -Circle=female
Shaded=have the trait Half-shaded=carriers

11 Turn and Talk: In what ways can a pedigree be helpful to a family
Turn and Talk: In what ways can a pedigree be helpful to a family? Provide evidence for your thinking.

12 Mapping chromosomes Karyotype is a picture of all of the chromosomes in a cell. They are stained and lined up from largest to smallest with X and Y last.

13 karyotype

14 Incomplete Dominance: Explain the phenotype of the offspring from these parents:
White rat and Black rat cross Flat Feet and Arched Feet

15 CoDominance: Explain the phenotype of the offspring from these parents:
White Bulldog and Brown Bulldog Type A Blood and Type B Blood

16 Blood Types


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