Presentation on theme: "The Father of Genetics Gregor Mendel Austrian Monk Born 1822 University of Vienna Math/Science Monastery Gardener True Breeding Peas Self Pollination Vs."— Presentation transcript:
The Father of Genetics Gregor Mendel Austrian Monk Born 1822 University of Vienna Math/Science Monastery Gardener True Breeding Peas Self Pollination Vs. Crossbreeding
Time Line 1866 Mendel publishes paper 1900 Mendel’s paper rediscovered 1902 chromosome theory of inheritance 1905 the term “genetics” coined 1950 base pairing discovered 1953 Watson & Crick deduce the structure of DNA
Pea Plants 7 Contrasting Traits 1. Round Skin Vs Wrinkled 2. Green Seed Vs Yellow 3. Grey Coat VS White 4. Smooth Pod Vs Constricted 5. Green Pod Vs Yellow 6. Flower Axial Vs Terminal 7. Tall Plant Vs Short
Mendel’s Principles of Genetics 1.Genes determine biological characteristics and are passed from parents to their offspring. 2. Some genes are dominant and some recessive. 3. Each adult has two copies of each gene and offspring receive a copy from each adult known as alleles. 4. Alleles segregate independently of each other and are then placed in a gamete (sperm or egg).(shuffle Number 2)
Segregation and Independent assortment Mendel’s Law of Segregation: 1 st Law 1.Alleles of the same trait are “segregated” or separated into their own gametes. 2. Alleles are segregated during Anaphase 1 and Anaphase 2 of meiosis as homologous chromosomes and then sister chromatids are pulled to the poles. Mendel’s Law of Independent Assortment: 2 nd Law 1. Chromosomes and their alleles separate randomly and independently for different traits. They do not determine each others assortment. 2. Chromosomes and their alleles assort independently of each other as homologous chromosomes line up during Metaphase 1 and chromatids in Metaphase Independent Assortment is not apparent phenotypically until the F2 cross when the expression of recessive alleles can be seen in the 9:3:3:1 outcome.
Mendel’s Law of Segregation
F 2 shows all possible outcomes as a result of independent assortment
Genetic Diversity 1.Cross-Over - swapping fragments of chromosomes during meiosis in Prophase 1 (1 st shuffle) 1.Independent Assortment - would alleles stay together? The F2 generation showed they do not. (2 nd shuffle) 2.Segregation - separation of alleles (3 rd shuffle 1.Environment (not genetic) (nature Vs Nurture)
Other Gene Expressions (not a dominant recessive expression) 1. Incomplete Dominance - carnations & Four O’clock plants 2. Codominance - chickens & cholesterol levels & cows 3. Multiple Alleles - still have two alleles but variations - blood Types & coat color in rabbits 4. Polygenic Traits - traits controlled by multiple genes - eye color & skin color 5. Multifactorial Trait - polygenic with environmental influence - fingerprints, height, weight & heart disease as well as those above - Mendelian ratios do not apply
1. Incomplete Dominance 2. Codominance Blending in one & two Blood Type AB 3. Multiple Alleles 4. Polygenic – skin color
White - Black Twins! The amazing conception happened after two eggs were fertilized at the same time in the womb. Both Kylie and her partner Remi Horder, are of mixed race. Their mothers are both white and their fathers are black. According to the Multiple Births Foundation, baby Kian must have inherited the black genes from both sides of the family, whilst Remee inherited the white ones.