Popular in Course
Popular in Biology
verified elite notetaker
This 3 page Reader was uploaded by Alec Sullivan on Sunday April 27, 2014. The Reader belongs to a course at University of Washington taught by a professor in Fall. Since its upload, it has received 99 views.
Reviews for Introductory Biology
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 04/27/14
Mendel Mono hybrid and di hybrid crosses Tuesolay April 15 ZED14 747 PM Chapter 141 Mende s Experimental System I Heredity transmission of traits from parents to offspring I Trait characteristic of an individual eg height membrane protein What Questions Was Mendel Trying to Answer I What are the basic patterns in the transmission of traits from parents to offspring I Two hypotheses 0 Blending inheritance traits observed in motherfather blend 0 Inheritance of acquired characters traits present in parents are modified through use and passed on to offspring The Garden Pea Served as the First Model Organism in Genetics I Inexpensive easy to group short generation time produce large of seeds I Model organism a species used for research because it is practical results can apply to other organisms I Each plant had different recognizable traits and mating could be controlled How Did Mendel Control Matings III Sef fertiization a fower s pollen falls on the female organ of the same flower III Crossfertilization transfer of pollen from one plant to another What Traits Did Mendel Study 9 Seven traits Seed color Seed shape Pod shape Pod color Flower color Flower and pod position Stem length 9 Phenotype observable trait 9 Pure line individuals that produce offspring identical to themselves when they are selfpollinated or cross w another pure line 9 Hybrids offspring from mating between true breeding parents that differ in one or more traits 0000000 Vocabulary for Mendelian Genetics Gene a hereditary factor that influences a particular trait Allele a particular form of a gene o the two alleles in a diploid may be the same or different Genotype a listing of the alleles in an individual o in diploids the genotype lists two alleles of each gene o in haploids the genotype lists one allele of each gene Phenotype an individual s observable traits can be observed at levels from molecule to the whole Biology 180 Page 1 organism influenced not dictated by the genotype Homozygous having two of the same alleles Heterozygous having two different alleles Dominant alleles an allele that produces its heterozygous and homozygous form dominance does not imply high frequency or high fitness Recessive allele an allele that produces its phenotype only in homozygous form phenotype quotrecedes or disappears in heterozygous individuals Reciprocal cross a cross in which the phenotypes of the male and female are reversed compared with a prior cross o If reciprocal crosses give identical results the sex of the parent does not influence transmission of the trait Testcross a cross between a homozygous recessive individual and an individual with the dominant phenotype but an unknown genotype o Usually used to determine whether a parent with a dominant phenotype is homoheterozygous X Linked referring to a gene located on the X chromosome o X Linked genes and traits show different patterns of inheritance in malesfemales Ylinked referring to a gene located on the Y chromosome o In humans Ylinked genes determine mae specific development Autosomal referring to a gene located on any nonsex chromosome an autosome or a trait determined by an autosomal gene o Mendel studied only autosomal genes and traits Chapter 142 Mende s Experiments with a Single Trait Parental generation adults used in an initial experiment cross F1 generation progeny first filial The Monohybrid Cross P ga1I11EllE5 rnlund parErlt FL Ft P Q3i391 E lE5 r Er Rf wri lllil d psarerlt RE RE o Results contrast blendinginheritance hypothesis Dominant and Recessive Traits I Monohybrid cross mating between parents w two different genetic determinant for the same trait I Wrinkled shape is recessive relative to round seed I Round seed is dominant relative to wrinkle seed I Individuals w the dominant phenotype do not necessarily have higher fitness than individuals w the recessive phenotype I Dominant and recessive identify only which phenotype is observed in individuals carrying two different genetic determinants for a given trait A Reciprocal Cross I Mendel wanted to test whether gender influenced inheritance of seed shape I Same outcome as before Biology 180 Page 2 Do Mendel s Results Hold for Other Traits I Foow up experiments showed 3 to 1 ratio in F2 generation in other traits Particulate Inheritance 0 Particulate inheritance hereditary determinants maintain their integrity from generation to generation they act as discrete entities or particles The Principle of Segregation o The two members of each gene pair must segregate into different gamete cells during the formation of eggs and sperm resulting in one allele of each gene within each gamete Predicting Offspring Genotypes and Phenotypes with a Punnett Square 0 Gamete genotype of one parent on horizontal row and other parent on vertical Biology 180 Page 3