EQ: How do genes influence the variety of organisms that exist? Non-Mendel Genetics EQ: How do genes influence the variety of organisms that exist?

Review Mendel Two types of alleles? Dominant and recessive Each gene requires 2 alleles Three allele combinations? Homozygous Dominant (HH) Heterozygous (Hh) Homozygous recessive (hh) Three Mendel's laws of inheritance Law of Dominance Law of Segregation Law of Independent Assortment

Mendel Review Monohybrid cross Dihybrid cross Mono = one Examine inheritance of one trait Punnett square with 4 grid boxes Grid boxes have 2 alleles (1 trait) Di = two Examine inheritance of two traits Punnett square with 16 grid boxes Grid boxes contain 4 alleles (2 traits)

Non-Mendelian Genetics There are a few types in inheritance patters that go beyond what Mendel discovered: Incomplete Dominance, Codominance, Polygentic

rr RR Rr Genotype = heterozygous Incomplete Dominance Genotype = heterozygous    Neither allele has complete dominance over the other, which results in a third phenotype. Heterozygous phenotype = mix/blend of the two parent alleles rr Tricks to help students remember: The two phenotypes meet in the middle of or intermediate = incomplete dominance. RR Rr Homozygous dominant Homozygous recessive Heterozygous RED WHITE PINK

r Incomplete Dominance r Rr Rr R Rr Rr R Using Mendel's laws of segregation and independent assortment, cross a Red flower (RR) with a white flower (WW) What are the possible genotypes and phenotypes of the offspring? Geno: 4 heterozygous (blend both dominant alleles) Pheno: 4 pink flowers r r Rr R Rr Rr Rr R

Heterozygous genotype Neither allele is dominant nor recessive Codominance Co = together Heterozygous genotype Neither allele is dominant nor recessive Phenotype- Both alleles fully and separately expressed (visible) Erminette

Non-Mendelian Genetics – Codominance A red colored flower (RR) is crossed with a white colored flower (WW).  Use Mendel's laws of segregation and independent assortment to complete the Punnett square. What are the possible genotypes and phenotypes of the offspring?  Genotype: 4 heterozygotes (RW)  Phenotype: 4 red and white flowers W W RW Use collaborative strategies while having students answer the last question. Answer: 1 red flower, 1 white flower and 2 red and white flowers R RW R RW RW

Don’t lose your marbles C – level 2 voice H – ask 3 then me A – complete the activity with your partner M- remain seated at your assigned table P – complete your activity sheet Success

Non-Mendelian Genetics – Polygenic Inheritance What do you think poly- means? What do you think –genic means? Polygenic inheritance is expressed when multiple genes each make a small contribution to the overall phenotype.    Allows for more than 2 or 3 variations in expressed phenotypes For example, skin color ranges from very fair to very dark skin shades.   At least 378 genes are involved in determining skin color.

Non-Mendelian Genetics – Polygenic Inheritance Punnett squares are complicated for polygenic inheritance. Other factors are involved with polygenic traits. Environment, nutrition Other polygenic traits: Height, eye color, hair color and body shape

Polygenic traits C- level 2 voice H- ask 3 before me Eye color is another example of polygenic trait. C- level 2 voice H- ask 3 before me A- complete polygenic lab M- remain seated at your table P- place lab on left side of INB Success

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