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Every organism has an inherited set of characteristics from their parent or parents. These are our genes. Genetics is the study of heredity.

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Presentation on theme: "Every organism has an inherited set of characteristics from their parent or parents. These are our genes. Genetics is the study of heredity."— Presentation transcript:

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3 Every organism has an inherited set of characteristics from their parent or parents. These are our genes. Genetics is the study of heredity.

4  Passing of genes from parent to offspring  Asexual reproduction: One parent  Low diversity  Essentially mitosis  Sexual reproduction: Two parents  High diversity  Mixes up DNA through meiosis

5  Father of genetics  Austrian monk born in 1822  A priest who studied science an mathematics  Worked at a monastery and taught high school

6  Carried out a series of experiments in the monastery’s garden  Observed fertilization process of garden peas

7  Crossbred truebreeding plants  Truebred – an organism who produce identical offspring to themselves  Observed 7 traits in offspring  Trait: A specific characteristic that varies based on what genes are inherited.

8 Pea flowers are normally self-pollinating, which means that sperm cells in pollen fertilize the egg cells in the same flower. The seeds then grow plants with the same characteristics as the single parent. Mendel wanted to produce seeds via cross-pollination (joining male and female reproductive cells from two different plants.)

9 Mendel accomplished cross- pollination by cutting away the pollen-bearing male parts & then dusting pollen from another plant onto the flower. This process produced seeds that had two different plants as parents. This made it possible for Mendel to cross- breed plants with different characteristics, and study the results.

10  P: Parent generation  Cross 2 truebreds  F 1 : Filial 1 generation  Produced hybrids: Resulting offspring from two truebred parents with different traits  Next, cross-fertilized hybrids from F 1 generation  F 2 : Filial 2 generation

11 1) Biological inheritance is determined by “factors” that are passed from one generation to the next. 2) Principle of dominance: states that some alleles are dominant and others are recessive.

12 Genes are the chemical factors that determine traits. The different forms of a gene are called alleles. Genes are located in specific positions on chromosomes.

13 Mendel had one more question remaining about his crosses… What happened to the alleles that disappeared? Ex: Cross a Tall and a Short plant and all of the F 1 offspring were tall. When Mendel allowed the F 1 generation to self pollinate, he was shocked to see the missing alleles reappear.

14 P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

15 P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

16 P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

17 Mendel correctly assumed that the allele for shortness was masked by the dominant tall allele, but was still puzzled on why it showed up again in the F 2. He knew that the short allele must have separated or SEGREGATED from the tall allele at some point. Mendel again correctly hypothesized that this segregation may have happened during sex cell or gamete formation. During gamete formation, alleles segregate so that each gamete carries a single copy of each gene.

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