8 Genetics and - Mendels Experiment with a single trait Heredity inheritance Phenotype observable features of an individual Pure line individuals

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Mendel’s Experiment with a single trait” - Heredity: inheritance - Phenotype: observable features of an individual - Pure line: individuals who breed offspring identical to themselves - Trait: any characteristic of an idividual - Hybrids: offspring mating between true breeding parents that differ in one or more traits. - Model organism: species were individuals are short lived, inexpensive to care for, able to produce large numbers and easy to manipulate experimentally. - F1 = offspring from the parental generation - Reciprocal cross: a set of mating where the mothers phentotype in the first cross is the fathers phenotype in the second cross and vise versa for the fathers first phenotype. - Reciprocal cross: used to determine whether it matters the genetic determinants are located in the male or female. - Dominant and recesiveness identify only which phenotype is observed in dividuals carrtyng 2 diff genetic determinants - Gene: hereditary determinant for a trait - Alleles: different versions of the same gene - The alleles found in a particular individual are called its genotype. - Principle of segregation: 2 alleles of each gene must segregate into different gamete cells during the formation of eggs and sperm in the parents as a result each gamete contains one allele of each gene. - Each gamete contains one allele because during the formation of eggs and sperms allels of each gene have to separate - Each gamete contains one allele of one gene - RR or rr = homozygous - F1 = heterozygous individuals - 3:1 phenotype ratio in F2 individuals, .25 - .5 - .25 genotype ratio - Particulate Inheritence: hereditary determinants maintain their integrity from generation to generation. Instead of blending together they act like discrete entities or particles - Genotype: the particular alleles found in a individual - Monohybrid cross: 3:1 ratio - For pundit square each unique gamete gets a column or row - Rr and RR should be present in 2:1 ratio, twice as many heterozygotes and homozygotes - Alleles do not blend together - Each gamete contain one allele of each gene Mendel’s experiment with 2 traits: - Dihybrid cross: mating between parents that are both heterozygous for 2 traits. ; ratio of 9:3:3:1 - Principle of independent assortment: alles of different genes are transmitted independently of one another. - Alles of different genes are transmitted independently of one another - Testcross: uses a parent that contributes ony recessive alleles to its offspring to help determine the genotype of the second parent. - The use of a homozygous recessive testcross can determine if the other parent is heterozygous results in 1:1:1:1 ratio Chromosome Theory of Inheritance
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- Meiosis reduces chromosome number by half and also explains the principle segregation and the principle of assortment - Chromosomes are composed of genes - Principle of segregation: The physical separation of alleles during anaphase of meiosis I
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This note was uploaded on 03/06/2012 for the course BIOLOGY 121 taught by Professor Hawk during the Spring '12 term at The University of British Columbia.

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8 Genetics and - Mendels Experiment with a single trait Heredity inheritance Phenotype observable features of an individual Pure line individuals

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