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