Gregor Mendel Austrian Monk The Father of Modern Genetics
The use of pea plants Mendel used pea plants for his studies…but why? Many different observable traits Reproduced very quickly He could control which plants reproduced with each other
Traits that he was observing Round vs. wrinkled pea shape Tall vs. short Yellow vs. green color Traits were easily seen from generation to generation Allele- alternative versions of a trait or gene…such as tall vs. short or T vs. t
Homozygous vs. Heterozygous Homozygous- The alleles in a pair are identical TT or tt Heterozygous- The alleles in a pair are different Tt
Genotype vs. Phenotype GenotypePhenotype The genetic make-up of an organism Bb, BB, or bb The outward appearance of an organism Example: Brown Hair, tall, blue eyes, etc.
Mendel’s Laws Rule of Unit Factors- each organism has 2 factors that control each of its traits You have 2 alleles for each trait…one from each parent!
Mendel’s Laws (continued…) Rule of Dominance- Within any characteristic one allele appears more often than the other. This may give the appearance that that allele is stronger and the other is weak. If you have a brown hair allele from mom and a blond hair allele from dad, you would only see brown because it is dominant to blond.
Mendel’s Laws (continued…) Law of segregation-Each organism can produce 2 different types of gametes because it has 2 different alleles. During fertilization, male a female gametes randomly pair to form 4 combinations of alleles
Mendel’s Laws (continued…) Law of Independent Assortment- Genes for different traits are inherited independent of each other.
Punnett Squares A chart used to solve genetic problems
Rules for Making a Punnett Square Female gametes (eggs) go down the side Male gametes (sperm) go across the top Capital letters = dominant Lower Case letters = recessive
Monohybrid Cross Showing only one trait.
Probability
Dihybrid Cross