Mendel: Fundamentals of Genetics
Gregor Mendel 1850’s…Austrian Monk Studied science and math…researched heredity using pea plants. Heredity- passing of characteristics from parents to offspring.
Mendel’s Experiment Mendel observed 7 different characteristics of pea plants He noticed each characteristic occurred in 2 contrasting traits
7 Characteristics Mendel Studied
Mendel’s Experiments: -Worked with pure plants, meaning always producing offspring with the same trait. -Parental generation: P1 generation. -Offspring of the P1 generation = F1 generation. -Offspring of the F1 generation = F2 generation
3 Steps to Mendel’s Experiment
Rule of Dominance -Mendel concluded that one factor (allele) in a pair may prevent the other from having an effect. He called this the dominant factor. -The allele that did not appear but appeared later was called the recessive allele.
Law of Segregation -Mendel concluded that alleles separate during meiosis. This means that each gamete produced only received one allele of the pair. When the gametes combine during fertilization, the offspring have two alleles controlling a specific trait.
Law of Independent Assortment -Mendel crossed plants that differed in two traits. For example, flower color and seed color. He figured out that the alleles for different traits are not connected and are distributed to gametes independently.
Chromosomes & Genes Genes- segment of DNA on a chromosome that controls a particular trait. Different forms of genes are called alleles. Letters are used to designate alleles. Capital letters = dominant alleles (G, T, H) Lower case letters = recessive alleles (g, t, h)
Genotype- genetic makeup of an organism Genotype- genetic makeup of an organism. Consists of the alleles that an organism inherits from its parents. For example HH, Hh, or hh. Phenotype- the physical appearance of an organism. (Example- purple flowers.)
Homozygous- both alleles of a pair are alike. HH or hh (Homozygous dominant or homozygous recessive) Heterozygous- alleles of a pair are different. Hh