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Mendelian Genetics. Genetics. The study if heredity Relatively new area of biology New information is being discovered even today!. Gregor Mendel. “Father of Genetics” Austrian Monk Formally educated in math Studied heredity in pea plants. Results of Mendel’s Pea experiments.
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Genetics • The study if heredity • Relatively new area of biology • New information is being discovered even today!
Gregor Mendel • “Father of Genetics” • Austrian Monk • Formally educated in math • Studied heredity in pea plants
Results of Mendel’s Pea experiments In the 1st filial (F1) generation all of the offspring showed the same trait (the dominant trait) When the F1 generation self-pollinated (formed the F2 generation), ¾ of the F2 generation showed the dominant trait & ¼ showed the recessive trait.
P (parent) generation were “pure-bred” for traits…they only carried the trait they showed! Mendel did not know about chromosomes, genes or DNA! “Factors” that Mendel talked about were actually ALLELES (versions of a gene)
“Factors” (alleles) are inherited from your parents. • You get 1 allele for each trait from each parent.
Mendel’s laws • Law of Dominance – some alleles show and some alleles are “hidden”. The traits that mask other traits are dominant traits. EX: Tall plant X Short plant all offspring are Tall Tall is the dominant trait!
Use capital letter to represent dominant allele • Use lower case letter to represent recessive allele EX: T = tall t = short
REMEMBER… Each organism has a pair of genes for each trait (diploid) TT = homozygous dominant (tall) Tt = heterozygous (tall, but carries an allele for short) tt = homozygous recessive (short)
2) Law of Segregation – alleles separate during the formation of Gametes. (During meiosis) REMEMBER- you get 23 chromosomes from each parent for a total of 46 chromosomes!
3) Law of Independent Assortment – each trait is independent or not linked to other traits. EX: Eye color is NOT linked to height!