 Who was Gregor Mendel (biographical information)?  What did he study?  Why did he use pea plants for his research?  What were his results?  What conclusions did he make (laws & rules)  Why is his work important?

 Considered the “Father of Genetics” for his important discoveries  Worked in the 1800’s in Austria; lived in a monastery  Used pea plants to study Heredity

 Mendel used pea plants for his research because they are easy to grow, easy to pollinate, and they have distinctive, observable traits  Mendel conducted Monohybrid crosses, in which he studied how one trait was inherited in pea plants  He cross-pollinated parents with opposite characteristics (P 1 generation)  He found that all of the offspring (F 1 generation) had the dominant trait  When he crossed two F 1 plants to make the F 2 generation, he found that the traits always appeared in a 3:1 ratio

 Mendel also studied how two traits were inherited – he referred to these as Dihybrid crosses  He found that when two heterozygous (hybrid) parents were crossed, the F2 generation showed a 9:3:3:1 ratio

 Mendel studied a variety of traits in pea plants for many years  Based on his conclusions, he developed several rules and laws of genetics that are used today to understand heredity  Although we now understand that there are many exceptions to Mendel’s rules, the heredity of many traits follows these patterns

 Rule of Unit Factors – each organism has two factors (genes) that control each trait - each different form of a gene is called an ALLELE - if an organism has two of the SAME allele, it is known as HOMOZYGOUS - if an organism has two DIFFERENT alleles, it is known as HETEROZYGOUS - the combination of alleles ( genes ) is known as the GENOTYPE, and the genotype determines the PHENOTYPE, which is the actual trait or appearance

 Rule of Dominance – the DOMINANT allele is the one that is observed (“stronger”), and the RECESSIVE allele is hidden  Law of Segregation – the two alleles for each trait separate when gametes are formed during meiosis, so that a parent passes on only ONE allele at random for each trait  Law of Independent Assortment – genes for different traits are inherited independently of one another; the genes you inherit for one trait do not influence your other traits