1. Mendelian Exceptions Chapter 11 Section 3

2. Mendel’s Principles Revisited Inheritance of biological _____________ is determined by individual units known as ______. During sexual reproduction, genes are passed from parents to _________. Two or more forms of the gene for a single _____ exist, some forms of the gene may be _________ and others may be recessive. characteristics offspring genes trait dominant

3. Mendel’s Principles Revisited Organisms typically have ____copies of each gene, (one from each _______) An organism’s _____ of genes (2 alleles) are segregated from each other when ________ are formed. Alleles for different ______ usually segregate _____________ of one another. (through meiosis) (Law of Independent Assortment) independently parent two gametes genes pair

4. Independent Assortment in Peas __ Round yellow __ Round green __ Wrinkled yellow __ Wrinkled green 9 3 3 1

5. Incomplete Dominance In incomplete dominance, neither allele is __________ so there is a blending of ______ when two different alleles for the same trait occur together. blend Colors blend together (______________ individuals = 3 rd phenotype) dominant traits heterozygous redwhitepink

6. Incomplete Dominance In Four O’ Clocks, if you cross a red _____ (which is always pure) with a white _____ (that is also always pure), you get a pink _____ (which is always hybrid / heterozygous RR WW RW RW

7. Incomplete Dominance In another flower, if red ____ and blue ____ flowers are crossed, they produce a 3 rd purple ____ flower What would be the genotype ratio and phenotype ratio if you crossed two purple flowers? RR BB RB

8. Incomplete Dominance Cross of two purple flowers ____ X ____ What are gamete possibilities? genotype ratio 1 RR : 2RB : 1BB phenotype ratio red : 2 purple : 1 blue Can you have a heterozygous red or hybrid blue flower? ___ B R RB BB RB RR RB redpurple blue RBRB no

9. Codominance Both _______ contribute to the phenotype of the organism by showing up simultaneously (at the same time) in heterozygous individuals. In cattle and horses, if you cross a pure ____ (RR) with a pure ______ (WW), you get (RW) which produces the color _____. alleles red white roan

10. Codominance These cattle or horses actually have both red and white hairs intermixed, or are spotted. Roan is a third ___________. If you cross a roan with a white… W W RW WWRW RW WW phenotype roan white

11. Codominance Andalusian chickens also show this pattern of inheritance. If you cross a black (BB) chicken With a white (WW) chicken You get black+white speckled (BW) chicken

12. Multiple Alleles In this pattern of inheritance, the genes have more than _____ alleles controlling them and are therefore said to have multiple alleles. No individual has more than _____ alleles, but there are more than _____ possible alleles in a population, so a ______ will be expressed in more than two forms. two two two trait

13. Multiple Alleles Blood type in humans is an example of this inheritance pattern. The ______ different blood groups: A, B, O, and AB Are produced by ______ different alleles: A, B, and O four three PhenotypeGenotype AAA or AO BBB or BO ABAB only OOO only

14. Multiple Alleles Examples of Blood type crosses

15. Polygenic Traits Traits controlled by two or more genes Show a wide range of phenotypes The phenotype is produced by the interaction of more than ________ of genes. 1 pair

16. Polygenic Traits These are called ___________ traits, which means “having _______ genes”. In humans, _____ color, _____ color, polygenic many skin eye

17. Polygenic Traits These are called ___________ traits, which means “having _______ genes”. In humans, _____ color, _____ color, and _____ color polygenic many skin eye hair

18. Polygenic Traits These are called ___________ traits, which means “having _______ genes”. In humans, _____ color, _____ color, and _____ color are just a few of the many traits __________ by many genes. polygenic many skin controlled eye hair