Mender’s law of segregation When two traits are studied the doctors tort one trait separate independently to the other pair tot factors- Mender’s law of independent assortment Mendel carried out further experiments for the other traits he observed which were predicted using formulas Mendel observed debris crosses to establish his second law of independent assortment He noted that when a tall plant with green pods crosses with a short Lana with yellow pods, each trait is separated and can lead to the result of a short green plant or a tall yellow plant. Every parent has two factors that code for a trait- genes (Egg) EGG- pure bred- green, egg- pure bred-yellow Monophonic would be Egg That’s the law of segregation One trait is dominant over the other- capital letter Phenotype- appearance Genotype- genes Describe the aspects of the experimental techniques used by Mendel that led to his success Valid and Reliable: Only changed one variable at a time Large sample size Repeated experiment xx
Established mathematical formula Accurate: Controlled environment greenhouse Ensured no accidental cross pollination Manual fertilization Reliable- consistent Accuracy- correct result that you were expecting Validity- valid, you’re doing what you want to do For 2 years he bred pure breeds in separate green houses which ensure accuracy Only compared one trait at a time- validity as it was his objective He tested various traits to confirm his ratio, he kept everything else constant Cross pollinated pure bred by hand- accuracy Removed the anther to remove risk of self pollination- accuracy He repeated the experiment hundreds of times Accuracy Validity Reliability Bred pure breeds in separate greenhouses Cross pollinated pure breeds by hand Removed anthers Only compared one trait at a time Tested various traits to confirm findings Repeated the experiment hundreds of times for each trait to reach consistent resultsOutline the reasons why the importance of Mender’s work was not recognized until some time after it was published Published his work in 1866 Work was recognized in 1900 Why was he ignored?
Findings were too progressive Little was known about cells and genetics He presented his work to 40 scientists low profile His work was different from the current belief of ‘blending’ He had no established reputation No prior research He was shy Born in 1822 Known as father of genetics Characteristics are determined by two factors in every individual FactorsвЂ?genes Alleles and genes Distinguish between the terms allele and gene, using examples Cells contain units of hereditary information called genes (on chromosomes) Genes influence specific characteristics, ‘e. One gene codes for eye color, another will code for hair color
Different variation of the same genes are called alleles Alleles for the gene height, tall (T) and short (t) Diploid individuals have two alleles for each gene Haploid cells have only one allele An individual can only have two alleles which are the ones passed by their parents Genotypes: homozygous and heterozygous Distinguish between homozygous and heterozygous genotypes in monophonic crosses Pure breed- homozygous- identical alleles (TTT or TTT) Hybrid- heterozygous- differing alleles (TTT) Phenotype as determined by dominant and recessive alleles Explain the relationship between dominant and recessive alleles and phenotype sing examples Genotype