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Applying Mendel’s Principles. Probability. Is the likelihood that something will happen. Expressed as a decimal, percentage, or a fraction. Genes combine according to the rules of probability For example, the chances of an organism being a male or female is 50%. Probability.
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Probability • Is the likelihood that something will happen. • Expressed as a decimal, percentage, or a fraction. • Genes combine according to the rules of probability • For example, the chances of an organism being a male or female is 50%. Applying Mendel’s Principles
Probability • Can be used to predict the outcomes of genetic crosses. Applying Mendel’s Principles
Probability • Predicts the average outcome of a large number of events. • Large numbers of offspring, will be closer to predicted values. Applying Mendel’s Principles
Genotype & Phenotype • Genotype is the genetic makeup of an organism. • Phenotype is the physical appearance of an organism that is the result of its genotype. Applying Mendel’s Principles
Punnett Square • Is a simple diagram that uses mathematical probability to predict the outcome of a genetic cross. Applying Mendel’s Principles
Independent Assortment Mendel Wondered if the segregation of one pair of alleles effects another pair. Performed an experiment that followed two different genes as they passed from one generation to the next. This experiment is known as a two-factor, dihybrid, cross. Single gene crosses are monohybrid crosses.
Independent Assortment Mendel crossed true-breeding round yellow peas with wrinkled green peas. All of the F1 offspring produced round yellow peas.
Independent Assortment The alleles for yellow round peas were dominant over the alleles for green wrinkled peas. This result did not support the independent assortment of genes.
Independent Assortment Mendel crossed the F1 plants to produce F2 offspring. This produced offspring that had phenotypes that were not found in their parents. This meant that genes that segregate independently do not influence each other’s inheritance.
Principle of Independent Assortment: States that genes for different traits segregate independently during the formation of gametes. Appyling Mendel’s Principles
A Summary of Mendel’s Principles The inheritance of biological characteristics is determined by individual units called genes, which are passed from parents to offspring. Where two or more forms (alleles) of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive
A Summary of Mendel’s Principles In most sexually reproducing organisms, each adult has two copies of each gene—one from each parent. These genes segregate from each other when gametes are formed. Alleles for different genes usually segregate independently of each other.
Practice Quiz for Mendel's Genetics http://anthro.palomar.edu/mendel/quizzes/mendqui1.htm