10-patterns-of-inheritance-160215185228.pdf (2).pptx

ppt for identifying phenotype and genotype ratio using the Punnett square

1. PRAYER

2. GOOD AFTERNOON

3. GOOD AFTERNOON

4. GOOD AFTERNOON

5. Patterns of Inheritance

6. Chromosome Review

7. Genetics Study of the patterns of inheritance • • Mendelian Genetics – – Gregor Mendel Pea plant experiments • • Grow easily Distinguishable characteristics – Round/Wrinkly, Yellow/Green, Tall/Short •Can control mating

8. Terminology •Allele –Alternate forms of a gene • • Recessive Allele –trait that is masked if a dominant trait is present. – – Dominant Allele –trait that exerts its effects whenever present – – Ex. Blue eyes Symbolized by capitol letter (B) Ex. Dwarfism, Huntington’s disease Symbolized by lower case letter (b)

9. Terminology •Genotype –Genetic makeup of an organisms – – – – – P Generation –Parental F1 –offspring of parent, first filial generation F2 –1stgeneration of offspring Homozygous –2 alleles that are the same (BB or bb) Heterozygous –2 different alleles (Bb) • • Phenotype –Observable characteristics –Brown eyes, brown hair, tall, short Generation –group of organisms born around the same time

10. Genetic Terminology Term Generations P F1 Definition Term Dominant and recessive Genotypes and Phenotypes Definition F2 Chromosomes and Genes Allele Gene Locus Chromosome First(parental) generation children (Latin filii)of generation P childrenof generation F1 macromolecules found in cells, consisting of DNA, protein and RNA unit of heredity of a living organism specific location of a gene, DNA sequence, or position on a chromosome one of a number of alternative forms of the same geneor genetic locus Mmutant Homozygous Heterozygous Phenotype True Breeding Dominant Allele Recessive Allele allele thatis always expressed if present allele that is only expressedif the dominant allele is not present individual contains two of the same allele of a gene contains two different alleles of a gene organism's observable characteristics or traits pure-bred, is an organism that always passes down a certain phenotypic trait to its offspring most common phenotype in nature physicalor genetic difference from a mutation in a gene Genotype Wild Type genetic makeup of a cell, an organism, or an

11. Tracking Inheritance • Punnett Square –diagram showing genotypes in a test cross – Monohybrid Cross –Mating between individuals that are BOTH heterozygous Dihybrid Cross –Mating between individuals that are heterozygous for 2 traits (genes) Test cross –a Punnett square done to figure out the genotype of an unknown • Always use a homozygous recessive individual with unknown • •

12. Genotypic ratio 1:2:1 (1 BB: 2 BB: 1 bb) (3 pink: 1 white) Phenotypic ratio 3:1 Monohybrid Cross

13. Dihybrid Cross Phenotypic ratio 9:3:3:1 (9 Smooth brown, 3 Smooth white 3 Curly brown 1 Curly white)

14. Laws of Segregation and Independent Assortment • Segregation -Two alleles of each gene are packed into separate gametes Assortment -The segregation of alleles of one gene does not influence the alleles for another gene – – – – Alleles move apart during meiosis Occurs during meiosis 1 –Metaphase • Alleles are RANDOMLY packaged in gametes Use Product Rule –The chance that 2 independent events will both occur = the product of individual chances that each event will occur Homologous chromosome move to opposite ends of Poles •

15. Laws of Segregation and Assortment

16. Product Rule

17. XA Y XA XAXA XAY Xa XAXa XaY