Presentation is loading. Please wait.

Presentation is loading. Please wait.

DNA Mutations & Genetics

Similar presentations

Presentation on theme: "DNA Mutations & Genetics"— Presentation transcript:

1 DNA Mutations & Genetics
Lewis Biology 2013

2 Concepts Covered this unit
Mutations (Point and Frame-shift) Diseases caused by Mutations Sickle Cell Anemia and Point Mutations Genetics and Heredity Gregor Mendel and the Pea Plants Monohybrid Crossing Alleles Mendelian Genetics Non-Mendelian Genetics Dominance vs. Recessive Co-Dominance Incomplete Dominance Multiple Alleles & Blood Typing Sex-Linked Traits Pedigree Analysis Chapters 10 & are a good resource to use for this unit! Please read ahead

3 Terms You will encounter this unit (at some point you will need this vocabulary in your notes)
Heredity Trait Genetics Gamete Fertilization Zygote Pollination Hybrid Allele Dominant Recessive Phenotype Genotype Homozygous Heterozygous Crossing over Diploid Haploid Egg Homologous chromosomes Meiosis Nondisjunction Sperm Sexual reproduction Carrier Fetus pedigree Co-dominance Incomplete dominance Multiple allele Polygenic inheritance Sex chromosome Sex linked trait Karyotype

4 Diseases covered this unit
Please research and read ahead about the following genetic disorders: Kleinfelter’s Disease Turner’s Syndrome Cystic Fibrosis Sickle Cell Anemia Trisomy 21 (Down Syndrome)

5 The exam for this unit The exam for this unit will be held between October 30-31st. This will be considered your Midterm Examination. Most of the material will cover: DNA, RNA, Protein Synthesis and Genetics—although older material will be on the exam. The midterm will be weighed twice (as two test grades) Please study ahead of time as it is comprehensive and cumulative. As a resource, utilize Chapters 10 & 12 in the Blue Glencoe Textbook

6 Dna mutations There are two general types of mutations Point and Frame-Shift Mutagen: something that causes a mutation Point Mutations: a genetic mutation in which only one of the nitrogenous bases is substituted (changed) to another). Only one amino acid is changed Frame-shift Mutations: a genetic mutation in which one of the bases is added or deleted. This causes the rest of the DNA sequence to shift, changing the ENTIRE DNA/AMINO ACID SEQUENCE. THIS IS THE MOST DANGEROUS MUTATION

7 EXAMPLES OF Point Mutation
Sickle cell anemia is caused by a point mutation. A single base is changed, causing the disease to occur (FYI, those who have sickle cell are resistant to Malaria) Normal Hemoglobin (blood) GGG-CTT-CTT-TTT Sickled Hemoglobin (blood) GGG-CAT-CTT-TTT Only one(1) of the amino acids will change

8 Examples of Frame-shift Mutations
One of the bases in a DNA sequence is either inserted or deleted, therefore causing the entire sequence to shift. This will change the entire DNA sequence, thusly changing the entire AMINO ACID SEQUENCE. THIS CAN BE LETHAL NORMAL SEQUENCE: ATC – GAT – TTA – AAG THE A WILL BE DELETED, AND THE REST OF THE BASES WILL SHIFT TO FILL ITS PLACE MUTATED SEQUENCE: ATC – GTT – TAA –AG…..

9 Assignment #1: Mutations worksheet
Complete the mutations worksheet on my website. This is to be completed on your own paper. The answers will be discussed on today’s meet (please remember guidelines for appropriate commentary) Lets not allow for immaturity to ruin the privileges of those who follow rules. Be sure to read the section on your worksheet about Sickle Cell Anemia.

10 Genetics & heredity Chapters 10 &12

11 Father of Genetics Gregor Mendel is the father of genetics (hence the term Mendelian Genetics). Mendel was an Austrian monk studied heredity (how traits are passed from parent to offspring) He was the first to be able to predict the outcome of one’s traits. This led to the field of genetics (branch of biology that studies heredity) He studied heredity using garden pea plants using the sex organs (yes, plants reproduce sexually..)


13 TERMS & ABBREVIATIONS Monohybrid cross: aka the ‘Punnett Square’, used to predict the traits of offspring P1: Parent generation (mom & dad) F1, F2, ..: Filial generations (the offspring, grandchildren etc.) Homozygous Dominant: AA Homozygous recessive: aa (this is the ONLY time recessive traits are shown) Heterozygous: Aa (the dominant trait is still expressed) Dominant: trait that is shown or expressed Recessive: trait that is hidden or disappears in the mating Alleles: forms of a gene

14 …more terms Joke: You’ve got some good jeans! Haha… Get it?? Phenotype= the Physical appearance (color, size, shape, etc.) Genotype = the gene or allele (Aa, AA, aa) Example: 75% of the Offspring were Heterozygous Aa (genotype), meaning, they have Yellow eyes (phenotype) 25% of the offspring were Homozygous recessive aa (genotype), meaning they have white eyes (phenotype)

15 Basics of the punnett square: Try this example
Alleles: Brown eyes: BB, Bb Blue Eyes: bb Problem: Mom has blue eyes, and Dad is Heterozygous for Brown eyes. Complete the Punnett Square and give the phenotype and genotype of the offspring A a a a

16 Basics of the punnett square: answer
Problem: Mom has blue eyes, and Dad is Heterozygous for Brown eyes. Complete the Punnett Square and give the phenotype and genotype of the offspring Alleles: Brown eyes: BB, Bb Blue Eyes: bb A a Aa aa a Answer: Phenotype: 50% will have brown eyes 50% will have blue eyes Genotype: 50% Aa (heterozygous) 50% (homozygous recessive) a

17 Assignment #2 Complete the Monohybrid Cross worksheet on my website. The worksheet has been upload, you may write your answers on your own paper OR print it at home! Do not forget the rules of Mendelian Genetics!!! If there is a capital letter (A, B, C…), this means the gene is dominant, and will mask (cover) the recessive gene (a, b, c)

18 …not sexual reproduction
Meiosis …not sexual reproduction

19 Remember… We covered Meiosis when we talked about Mitosis. Meiosis is a cell division of gametes… In other words---it’s how guys make sperm, and ladies make eggs (ladies, you’re born with the eggs you have ) Guys continue Meiosis until they’re old…yuck Meiosis is NOT SEXUAL REPRODUCTION

20 meiosis In Meiosis, it’s a way of taking a person’s 46 chromosomes, and dividing them in half—so that parents only pass 23 chromosomes onto their offspring. You’re the perfect blending of both of your parents. 46 chromosomes in dad’s sperm / 2 (meiosis) = 23 chromosomes 46 chromosomes in mom’s eggs / 2 (meiosis) = 23 chromosomes 23 chromosomes + 23 chromosomes = YOU 

21 Review: Mitosis vs. Meiosis
Number of Divisions 1 2 (Meiosis I & Meiosis II) Number of daughter cells 2 4 Purpose Making new body cells (liver, hair, skin, etc.) “somatic cells” Making new sex cells “gametes” (sperm & eggs) Chromosome # Diploid (2n) Haploid (n) -half

22 Somatic cell (Mitosis)
Meiosis vs mitosis Organism Somatic cell (Mitosis) Diploid (2n) Gamete (meiosis) Haploid (n) Fruit fly 8 4 Garden pea 14 7 Corn 20 10 Tomato 24 12 Leopard frog 26 13 Apple 34 17 Human 46 23 Chimpanzee 48 Dog 78 39 Adder’s tongue fern 1260 630

23 Events in Meiosis Crossing over
Crossing Over: Occurs in Prophase I, where the chromosomes break, and exchange genetic material Nondisjunction: where the chromosomes fail to separate during Meiosis, this causes Trisomy 21 (Down Syndrome) Crossing over

24 …non-mendelian genetics
To be continued …non-mendelian genetics

Download ppt "DNA Mutations & Genetics"

Similar presentations

Ads by Google