Genetics: From Genetic Screening to Plant B reeding

1. Genetics:From Genetic Screening to Plant Breeding Joseph Geissler Newark Science Park High School Mrs. Paulose

2. Lesson Objectives • What is genetics? • The study of heredity in an organism or population • The study of variation in an organism or population • How can we investigate genetics? • Punnett Squares • Mendelian Patterns of Inheritance • Complete Dominance • How will you used these principles to grow tall hairy plants???

4. Genotype vs Phenotype • Genotype- the genetic makeup of an organism • Hereditary information, the sequence of alleles • i.e. RR, Rr, rr • Phenotype- the expression of a genotype in the appearance or function of an organism • An physical, observable trait • i.e. size, shape, color, growth

6. Genetic Nomenclature • Allele-represents one copy of a gene; gene expression is dependent on the strength of the two alleles • Monohybrid cross- investigation of one trait • Dihybrid cross- investigation of two traits • Dominate trait: the presence of only one allele is needed for gene expression • Recessive trait: both alleles must be present for gene expression • Capital letters represent a dominate trait • Lower case letters represent a recessive trait

7. Types of Genotypes • Homozygous genotype :: RR or rr • Both alleles are the same (dominate or recessive) • True-breeding organisms are homozygous for a particular trait • Heterozygous genotype:: Rr • Contains mixed alleles • Observed in F1 plants of true-breeding cross

8. Punnett Squares of Probability Monohybrid cross of two heterozygous organisms Monohybrid cross of two true-breeding organisms R r R R R r RR Rr r r Rr Rr Rr rr Rr Rr 4 Dominate: 0 Recessive 3 Dominate : 1 Recessive

9. Autosomal Dominant Disorders For inheritance, only one parents needs to be affected One dominant allele confirms phenotype Huntington’s Disease Hypercholesterolemia

10. Autosomal Recessive Disorders For inheritance, both parents must be either affected or a carrier Two recessive alleles confirms phenotype Sickle-cell Anaemia Cystic Fibrosis Autosomal recessive disorders can be lost and reappear several generations later

11. X-Linked Recessive Disorders Disorder is passed to a boy from its mother, who is a carrier of the disease Hemophilia Color blindness

12. Gregor Mendel’s Investigation ofPea Plant (1860s) Determined dominant and recessive traits of pea plants by performing monohybrid crosses Self-pollinating and cross pollinating techniques used to investigate individual traits

13. Parental Generation Cross pollination of two true breeding plants R R r r Rr Rr F1 generation Rr Rr So, what is the phenotype of F1?

14. F2 Generation Self-fertilization cross of F1 generation plants R r R r RR Rr Rr rr Genotypic Ratio 1 RR : 2 Rr : 1 rr Phenotypic Ratio 3 Round : 1 Wrinkled

15. Incomplete Dominance Phenotype is an intermediate between the parents Genotypic Ratio 1 RR : 2 Rr : 1 rr Phenotypic Ratio 1 red : 2 pink : 1 white

16. Blood Type Multiple alleles A,B, and i

17. Tall and Hairy • Two advantageous traits a plant can possess it to be tall and hairy. • For this experiment, you will apply your knowledge of botany and genetics to generate true-breeding plants for these traits. • Thanks to Mendel, we can accurately predict the outcomes of our crosses and do not need years of experiments to do so.

18. LETS PLANT