Presentation on theme: "Gregor Mendel ( ) The Father of Genetics Mendelian Genetics"— Presentation transcript:
1Gregor Mendel (1822-1884) The Father of Genetics Mendelian Genetics 3/27/2017Gregor Mendel ( )The Father of GeneticsThis has been modified from the original ppt Oct. 2011copyright cmassengale
2Gregor Johann Mendel Austrian monk Mendelian Genetics3/27/2017Gregor Johann MendelAustrian monkStudied the inheritance of traits in pea plantsDeveloped the laws of inheritanceMendel's work was not recognized until the turn of the 20th century
3copyright cmassengale Mendelian Genetics3/27/2017Gregor Johann MendelBetween 1856 and 1863, Mendel cultivated and tested thousands of pea plantsHe found that the plants' offspring retained traits of the parentscopyright cmassengale
4Particulate Inheritance Mendelian Genetics3/27/2017Particulate InheritanceMendel stated that physical traits are inherited as “particles”Mendel did not know that the “particles” were actually Chromosomes & DNAcopyright cmassengale
5copyright cmassengale Mendelian Genetics3/27/2017Why peas, Pisum sativum?Can be grown in a small areaProduce lots of offspringProduce pure plants when allowed to self-pollinate several generationsCan be artificially cross-pollinatedcopyright cmassengale
6Mendel and His Peas Mendel tested 7 traits: Flower color Flower positionSeed colorSeed shapePod shapePod colorPlant height
7Mendel and His PeasMendel crossed flowers that were true-breeding for each characteristic.He crossed a purple (PP) flowered plant with a white (pp) flowered plant. (Parent Generation)
8Mendel and His PeasPurple Parent (PP)The first generation (F1) of plants all had purple flowers.Where did the white color go??White Parent (pp) (Pp)(Pp) (Pp)
9Mendel and His PeasMendel took two of his first generation (F1 x F1) purple flowered plants and crossed them together.In the second generation (F2) he had 3 purple flowered plants, and 1 white flowered plant.Purple Parent (Pp)Purple Parent (Pp)(PP) (Pp) (Pp) (pp)
10Mendel and His PeasMendel noticed in the first generation, all of the white flowers seemed to disappear.He called this a recessive trait.The white color faded into the background at first.It showed up in the next generation when he pollinated the flowers.
11Mendel and His PeasThe color (purple) that seemed to mask over the recessive color was named the dominant trait.
12Mendel and His PeasMendel was responsible for figuring out that each plant carried two sets of instructions for each characteristic (one from the “mom” and one from the “dad”).Like many scientists, his work was not accepted until after his death.
13Let’s Review1. If you crossed a true-breeding black rabbit with a true-breeding white rabbit, all of the offspring would be black. Which trait is dominant in rabbits: black fur or white fur?2. Which trait is recessive?
14AnswerBlack Rabbit (BB)The trait for black fur is dominant over the trait for white fur. The white fur trait is recessive.White Rabbit (bb) (Bb)(Bb)
17Mendel and His Peas Vocabulary Heredity- the passing of traits from parent to offspring.Self-pollinate- A plant is often able to pollinate by itself because it contains both the male and female reproductive structures. This only requires 1 parent.
18Mendel and His Peas3. True-breeding- all of the offspring will have the same trait as the parent when self-pollinatedFirst-generation- the very first set of offspring from two parentsDominant trait- the trait observed when at least one dominant allele for a characteristic is inherited
19Mendel and His Peas6. Recessive trait- a trait that is apparent only when two recessive alleles for the same characteristic are inheritedGenes- a segment of DNA that carries hereditary instructions and is passed from parent to offspringAlleles- multiple forms of the same gene
20Mendel and His PeasGenotype- an organisms inherited combination of alleles10. Phenotype- an organisms inherited appearance