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Genetics. Vocabulary Terms Working Problems Monohybrid Crosses. Heredity and Genetics. Heredity - the passing of traits (characteristics) from parents to offspring Genetics - the branch of biology that focuses on heredity. Gregor Mendel. Father of Genetics.
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Genetics Vocabulary Terms Working Problems Monohybrid Crosses
Heredity and Genetics Heredity- the passing of traits (characteristics) from parents to offspring Genetics- the branch of biology that focuses on heredity
Gregor Mendel Father of Genetics
During his early years at the monastery, Mendel began studying and breeding mice. The bishop was not pleased.
Mendelian Theory of Heredity(the foundation of genetics) • For each inherited character, an individual has two copies- one from each parent • There are different • versions of genes= alleles For example, the gene for flower color in peas can exist in a “purple” version or a “white” version
When a trait has two forms and one trait is expressed over the other, the trait that shows up isDOMINANT. Dominant traits are represented by upper case letters. B - brown
When a trait has two forms, the trait that is hidden or masked isRECESSIVE. Recessive traits are represented by the same letters as dominant traits but lower case. b - blue
An individual having two like genes for a trait, such as BB or bb, is HOMOZYGOUS. HOMO = SAME These individuals can also be called pure. examples: BB, bb, PP, ww
An individual that has two unlike genes for a trait is HETEROZYGOUS. HETERO = DIFFERENT These individuals can also be called hybrid. examples: Tt, Ss, Rr, Ww
Modern Terms Genotype- the genetic makeup of an organism (the set of alleles an individual has) Ex. PP or Pp Phenotype- the physical appearance of an organism Ex. Purple
MONOHYBRID CROSS: shows the possible offspring for one trait B b Bb BB B b bb Bb Bb x Bb B: Brown b: white Genotypic Ratio: (BB: Bb: bb) - 1 : 2 : 1 Phenotypic Ratio: (Dom: Rec) 3 brown : 1 white
Practice #1! Cross a HOMOZYGOUS dominant individual with a HETEROZYGOUS one using the same trait as the previous problem. B B B BB BB Bb Bb b
Offspring Genotype: _____% homozygous dominant _____% homozygous recessive _____% heterozygous Offspring Phenotypes: _____% brown _____% white 100 50 0 0 50 What is the GR? What is the PR? 2 : 2 : 0 4 : 0
Practice #2! Cross a HOMOZYGOUS recessive individual with a HETEROZYGOUS one using the same trait as the problem before. b b What is the GR? 0 : 2 : 2 B Bb Bb What is the PR? 2 : 2 b bb bb