Chapter 14 - Introduction to the Genetics Notes

Chapter 14 - Introduction to the Genetics Notes -...

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GENETICS-Chapter 14 Observable characteristic =  TRAIT Alternative choices for a gene = ALLELES DOMINANT  allele hides the recessive allele RECESSIVE  allele is hidden by dominant allele if it is present HOMOZYGOUS  organisms have two of the same alleles for a trait (EX: TT or tt) HETEROZYGOUS  organisms have two different alleles for a trait (EX: Tt) PHENOTYPE = character that is expressed; “way it looks” GENOTYPE = genetic makeup;  “what genes it has” TRUE BREEDING PARENTS in genetic cross = PARENTAL ( P 1 ) generation Their offspring = first filial generation ( F 1 ) Off spring of the F 1  generation = SECOND FILIAL generation ( F 2 ) MENDELIAN INHERITANCE   MONOHYBRID CROSSES  – cross to study only ONE character     Aa X Aa = 3:1 ratio LAW of SEGREGATION  = two alleles separate during gamete formation               (separation of homologous partners during ANAPHASE I) DIHYBRID CROSS - cross to study TWO characters   LAW of INDEPENDENT ASSORTMENT = Each pair of alleles segregates (separate) independently in meiosis     Maternal and paternal chromosomes mix up in different combinations during gamete formation (ANAPHASE I) AaBb X AaBb =  9:3:3:1 ratio 9 = dominant trait 1/dominant trait 2 3 = dominant trait 1/recessive trait 2 3 = recessive trait 1/dominant trait 2 1 = recessive trait 1/recessive trait 2 For TRIHYBRID crosses or if parents NOT HETEROZYGOUS: 
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This note was uploaded on 02/14/2012 for the course BIO 151 taught by Professor Grinblat during the Fall '08 term at Wisconsin.

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Chapter 14 - Introduction to the Genetics Notes -...

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