Who is Gregor Mendel and What about his Peas?

Gregor Johann Mendel (1822 – 1884) was an Austrian monk who was often called “the father of genetics.”Gregor Johann Mendel (1822 – 1884) was an Austrian monk who was often called “the father of genetics.” Genetics is the study how traits are passed from one generation to another.Genetics is the study how traits are passed from one generation to another.

Mendel was the first person to trace the characteristics in a living thing (pea plants).

He then came up with the idea of dominant and recessive traits.

Seven traits of Mendel’s peas 1.Flower color is purple or white 2.Flower position is axil or terminal 3.Stem length is long or short 4.Seed shape is round or wrinkled 5.Seed color is yellow or green 6.Pod shape is inflated or constricted 7.Pod color is yellow or green

By cross-breeding common pea plants (Pisum sativum) over many generations, Mendel discovered that certain traits show up in offspring without any blending of parent characteristicsBy cross-breeding common pea plants (Pisum sativum) over many generations, Mendel discovered that certain traits show up in offspring without any blending of parent characteristics

Purebred - offspring that are the result of mating between genetically similar kinds of parents--the opposite of hybrid. Purebred is the same as true breeding.Purebred - offspring that are the result of mating between genetically similar kinds of parents--the opposite of hybrid. Purebred is the same as true breeding. Hybrids - offspring that are the result of mating between two genetically different kinds of parents--the opposite of purebred.Hybrids - offspring that are the result of mating between two genetically different kinds of parents--the opposite of purebred.

In cross-pollinating plants that either produce yellow or green peas exclusively, Mendel found that the first generation always has yellow peas. However, the next generation has a 3:1 ratio of yellow to green. A 3:1 ratio means the 3 plants will produce yellow peas (Dominant) to 1 plant that will produce green peas (Recessive)

Mendel’s Laws of Inheritance 1.The Law of Dominance 2.The Law of Segregation 3.The Law of Independent Assortment

The Law of Dominance –In a cross of parents that are pure for the same traits, only one form of the trait will appear in the next generation. (YY) –Offspring that are hybrid for a trait will have only the dominant trait in the phenotype. (Yy)

The Law of Segregation Alleles for a trait are "recombined" at fertilization, producing the genotype for the traits of the offspring.

The Law of Independent Assortment Alleles for different traits are distributed to sex cells (& offspring) independently of one another.

Quiz on these notes tomorrow Tomorrow, What is a Punnett Square? Ticket out the door, What are Mendel’s three laws of inheritance, use your notes