Meiosis and Genetics

1. Meiosis and Genetics

2. Genetics is all about Inheritance Meiosis -- The process in which cells divide in order to pass on its chromosomes to off spring. Produces 4 daughter cells from 1 parent cell Each daughter cell is called a haploids (half the DNA) We call these Daughter cells “gametes” Each gamete is genetically different

3. Both Mom and Dad undergo Meiosis Mom Dad Egg Sperm Fertilization Zygote

4. Male (Dad) Female (Mom) Fertilization

5. Genetics is all about chances. Mom Dad Egg Sperm Fertilization What are the chances of this sperm and egg will come together? Zygote

6. Come questions in Genetics… What are the chances our baby will have a disease? What genes will our baby have? What will our baby look like? How does our baby have blue eyes, when we both have brown eyes?

7. Miracle of Life

8. Let’s review Chromosomes Chromosomes are made of DNA. Chromosomes have bands on them that we call genes. Each Gene codes for the production of Proteins. Proteins are the features that we see.

9. Let’s look at a Karyotype • Remember Karyotypes? • How many chromosomes in a human cell? • How many homologous pairs? Remember you get one set of chromosomes from Mom and the other from Dad

10. Let’s look at Chromosome 18 further Each band represents a gene. Remember a gene is a segment of DNA that codes for a particular protein. The proteins are the things we see.

11. Let’s assign letter to a gene on chromosome 18 Remember a Chromosome is made up of 2 strands of DNA So let’s assign the letter “B” to a gene on the chromosome from Dad And let’s assign the letter “b” to a gene on the chromosome from Mom B B b b

12. During Meiosis what happens to these genes?

13. Let’s talk some Genetic Terminology Terms to know: Allele – a single gene on a DNA strand. Here we got 4 alleles! Hetero- = “Different” - zygous= individual; diploid cell Dominant = “B” is the expressed allele Recessive = “b” an allele whose gene in sometimes not expressed. Genotype is the combination of alleles Bb B B b b We would consider this cell a Heterozygous cell.

14. A gene is a locatable region of DNA, corresponding to a unit of inheritance. Allele: alternative form of a gene True definitions:Gene v. Allele Ex. Allele that codes for blue eyes + an allele that codes for brown eyes Ex. Gene that codes for eye color This homologous pairs have the same genes But different alleles

15. Let’s talk Some Genetic Terminology What is a Gene? What is SNPs? Where do Genes come from?

16. Bellringer: Using Terminology • Heterozygous or Homozygous dominant or recessive? Hh – ZZ – aa - bb – Nn- VV – Cc – ee – Dd – PP –

17. Well if Genes (or Genotypes) refer to DNA, what about the proteins? Phenotypes - an organism's observable characteristics or traits

18. Bellringer 2: Using Terminology • Genotypes v. Phenotypes Blonde hair – Heterozygous dominant – XY – ee – Tongue curling – Hitchhiker’s thumb – Aa – Large Nostrils – MM – webbed toes –

19. What causes Diversity in living organisms?

20. Mutations • a change in DNA which may or may not get passed on. Gene Mutations –Affect Nucleotides Chromosomal Mutations – Affect Genes If chromosomal Mutations are sever enough, serious problems can result.

21. 2) Crossing Over Homologous pair of Chromosomes swap genes. Why is Crossing-Over Not Considered a Mutation?

22. 3) Mendel’s Law of Independent Assortment

24. How do we determine probability? Punnett Squares - a diagram that is used to predict an outcome of a particular cross or breeding experiment.

25. Monohybrid Crosses – Complete Dominance Cross a Heterozygous Brown eyed Male with Homozygous recessive Female B b Alleles Brown eye= B Blue eye = b Bb bb b b Bb bb Genotypic Ratio: 1 Bb : 1 bb Phenotypic Ratio: 1 Brown Eyes : 1 Blue Eyes

26. Bell RingerQ: In dogs, wire hair (S) is dominant to smooth (s). In a cross of a homozygous wire-haired dog with a smooth-haired dog, what will be the phenotype of the F1 generation? A: Genotypic Ratio: Phenotypic Ratio:

27. Monohybrid Crosses – Incomplete Dominance Incomplete Dominance Video

28. Monohybrid Crosses – Incomplete Dominance Cross a Red Plant with a White Plant R R Alleles Red = R White = W RW RW W W RW RW Genotypic Ratio: 1 RW Phenotypic Ratio: 1 Pink Flowers

29. Complete Dominance v. Incomplete Dominance

30. Monohybrid Crosses – Co-dominance Co-dominance Video

31. Monohybrid Crosses – Co-dominance Cross a Red Plant with a White Plant R R Alleles Red = R White = W RW RW W W RW RW Genotypic Ratio: 1 RW Phenotypic Ratio: 1 Red and White Spotted Flowers

32. Complete Dominance v. Incomplete Dominance v. Co-dominance

33. Dihybrid Crosses Dihybrid Crosses

34. Multiple Alleles and Blood Types Multiple Alleles and Blood Types