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Genetics: The Science of Heredity

Genetics: The Science of Heredity. What is Heredity?. Gregor Mendel : Known as the Father of Genetics, he unlocked the key to understanding heredity using pea plants . He was able to obtain predictable , repeatable results using

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Genetics: The Science of Heredity

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  1. Genetics: The Science of Heredity What is Heredity?

  2. GregorMendel: Known as the Father of Genetics, he unlocked the key to understanding heredity using pea plants. He was able to obtain predictable, repeatable results using plants that could both self-pollinate & cross-pollinate. Hereditythe passing of traits/physical characteristics from parents to offspring Geneticsthe scientific study of heredity Fertilizationthe joining of egg and sperm cell (the beginning of the formation of new organism)

  3. Genessegments of DNA that carry hereditary instructions located on chromosomes & passed from parent to offspring (factors that control a trait) Allelesalternative forms of a gene that govern the same characteristics (ex. Eye color) Dominant traittrait observed when at least one dominant allele for a characteristic is inherited Recessive traittrait that is apparent only when 2 recessive alleles for the characteristic are inherited Homozygous/Purebredhaving 2 copies of the same allele for a trait (ex. HH or hh) Heterozygous/Hybridhaving 2 different alleles for a trait (ex. Rr or RW)

  4. Probability & Heredity Probabilitythe mathematical chance that an event will occur PunnettSquare(designed by Reginald C. Punnett) a chart that shows all the possible ways alleles can combine in a genetic cross Parent generation(Purebred purple flowers - PP x Purebred white flowers - pp) P P p p F2generation (self pollination of the offspring from the F1 generation: Pp x Pp) P p P p Genotypethe inherited combination of alleles; genetic make up Phenotypean organism’s inherited appearance; visible appearance

  5. Patterns of Inheritance Codominanceboth alleles for a gene are expressed equally (and individually) Incomplete dominanceone allele is only partially dominant (blending occurs) Multiple Allelesthree or more possible alleles determine the trait (an organism can still only inherit 2 alleles for a gene, one from each parent, but there are more possible genotypes with multiple alleles than with just 2 alleles; example = blood type) Polygenic Inheritancemore than one gene affects a trait (broad range of genotypes: human height, skin color, and eye color) Inherited Traittraits organisms are born with (height, freckles, eye color) Acquired Traittraits organisms acquire (language a person speaks, haircuts, piercings, tattoos)

  6. Chromosomes & Inheritance Chromosomecoiled structure of DNA & protein that forms in the nucleus during cell division; passed from one generation to the next Chromosome Theory of Inheritancegenes pass from parents to their offspring on chromosomes Meiosis Meiosis produces new cells with½the usual number of chromosomes. This process creates sex cells. The chromosomes are copied/duplicated onlyonce& nucleus divides twice.

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