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Genetics the study of inheritance

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Presentation on theme: "Genetics the study of inheritance"— Presentation transcript:

1 Genetics the study of inheritance

2 There are 2 types of cell division: ●Mitosis- growth and repair involved in cells replicating themselves and all of their DNA into exact copies of original cells ●Meiosis- sexual reproduction combining sperm & egg to produce an new and original organism that has half of it’s DNA from each parent into a original and unique combination of traits

3 Gregor Mendel Father of Genetics Austrian monk discovered heredity principles studied pea plants discoveries-shorts-genetics.htm

4 What Is Heredity? Crossing Pea Plants Mendel devised a way to cross-pollinate pea plants.

5 Common traits Mendel identified in Pea Plants: seed shape- round vs. wrinkled seed color-yellow vs. green pod shape-pinched vs. smooth pod color-green vs. yellow flower color-purple vs. white flower position-top of stem vs. side of stem stem height- tall vs. short

6 Alleles in Pea Plants Mendel studied the inheritance of seven different traits in pea plants. What Is Heredity?

7 Results of a Cross In Mendel’s crosses, some forms of a trait were hidden in one generation but reappeared in the next. What was surprising about the offspring in the F 2 generation? What Is Heredity?

8 Vocabulary/Term List asexual reproduction sexual reproduction heredity trait genetics purebred parental P1 generation First filial F1 generation Second filial F2 generation offspring gene allele dominant recessive hybrid probability Punnett square phenotype genotype homozygous heterozygous

9 Sample Crosses If a purebred tall pea plant with was cross pollinated with a purebred short pea plant describe it's offspring: Parent (P) Generation- First Filial (F1) Generation- Second Filial (F2) Generation-

10 Sample Crosses Part 2 If a purebred pea plant with purple flowers was cross pollinated with a purebred pea plant with white flowers describe it's offspring in each: Parent (P) Generation- First Filial (F1) Generation- Second Filial (F2) Generation-

11 Sample Crosses Part 3 If a purebred pea plant with wrinkled seeds was cross pollinated with a purebred pea plant with round seeds describe it's offspring in each: Parent (P) Generation- First Filial (F1) Generation- Second Filial (F2) Generation-

12 A GREAT visual representation!

13 How to Make a Punnett Square What are the steps in using a Punnett Square to find the probabilities of a genetic cross? Probability and Heredity

14 Describing Inheritance An organism’s phenotype is its physical appearance. Its genotype is its genetic makeup. Complete the missing information in the table. Probability and Heredity

15 Punnett squares

16 Punnett Square-draw, label & complete Y Y y A homozygous pea plant with yellow seeds is crossed with a homozygous pea plant with green seeds. Describe the results in: percentages, ratios and fractions & use the terms heterozygous and homozygous in your results Phenotypes of each plant: Genotype of each plant

17 Punnett Square- Draw, label & complete Y y Y y Describe the results in: percentages, ratios and fractions & use the terms heterozygous and homozygous in your results Phenotypes of each plant: Genotype of each plant A heterozygous pea plant is crossed with another heterozygous pea plant with both with yellow seeds.

18 Punnett Square Practice: For each sample question fill in the Punnett square and describe the offspring in the F1 generation. Include: · Genotypes (Percentages, ratios, fractions of alleles) · Phenotypes (Percentages, ratios, fractions of each physical appearance) Sample #1: In Guinea pigs black fur color is dominant over white fur color. Suppose a homozygous black male guinea pig mated with a heterozygous black female guinea pig. (P) Parent Alleles: F1 Generation: Sample #2: In Guinea pigs Smooth fur is dominant over Cow licked fur. Suppose a heterozygous smooth male guinea pig mated with a homozygous cow licked female guinea pig. (P) Parent Alleles: F1 Generation: Sample #3: In Guinea pigs Solid fur color is dominant over Calico fur color. Suppose a homozygous Solid male guinea pig mated with a Calico female guinea pig. (P) Parent Alleles: F1 Generation:

19 Dihybrid crosses Sample #4: In Guinea pigs Black fur color is dominant over White fur color & Solid fur color is dominant over Calico fur color. Suppose a homozygous Solid black male guinea pig mated with a heterozygous Calico black female guinea pig. What would the offspring be like? (P) Parent Alleles: F1 Generation: Sample #5: In Guinea pigs Smooth fur is dominant over Cow licked fur and Black fur color is dominant over white fur color. Suppose a heterozygous Black & Smooth haired Male mated with a White & Cow licked haired female guinea pig. What would the offspring be like? (P) Parent Alleles: F1 Generation: Sample #6: In Guinea pigs Black fur color is dominant over White fur color & Solid fur color is dominant over Calico fur color. Suppose a heterozygous Solid black male guinea pig mated with a homozygous Calico black female guinea pig. What would the offspring be like?

20 DiHYbrid Crosses enetics/problem_sets/dihybrid_cross/03t.html

21 Vocabulary/Terms List Part 2: Mendel’s experiments with pea plants led to an understanding of how traits are controlled by genes. However, some traits are not controlled by genes with only 2 possible alleles. There are 4 other complex patterns of inheritance: Give an explanation of each below: Include examples!!! o Incomplete dominance- o Codominance- o Multiple alleles- o Polygenic inheritance- Define: Meiosis- What does the chromosome theory of inheritance state? Compare and Contrast the processes of Mitosis and Meiosis: be sure to include when/what each is used for and in what types of cells https://www.youtube.com/watch?v=zGVBAHAsjJM

22 Blingwings An imaginary insect called the blingwing has three alleles for wing color: R (red), B (blue), and Y (yellow). 1.What are the 6 possible allele pairs that can be inherited? 2. Suppose the 3 alleles are codominant, what wing color would each pair of alleles produce? Patterns of Inheritance

23 Nature: DNA, Genes and Chromosomes Genes make you who you are.

24 Genes hold the key to heredity A gene is a short segment of DNA that contains the instructions for how to make one (or more) proteins. Each protein carries out a specific function within our body. MS, HS – LS3A

25 Chromosomes and Inheritance Paired Up Sutton studied grasshopper cells through a microscope. He concluded that genes are carried on chromosomes.

26 A Pair of Chromosomes Chromosomes in a pair may have different alleles for some genes and the same alleles for others. Is the organism homozygous or heterozygous? Chromosomes and Inheritance

27 Meiosis During meiosis, a cell produces sex cells with half the number of chromosomes. The correct number is restored when sperm and eggs combine!


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