INTRODUCTION TO GENETICS The science of inheritance Parents

INTRODUCTION TO GENETICS § The science of inheritance § Parents and offspring § heredity is the set of characteristics an organism receives from his parents

INTRODUCTION TO GENETICS

INTRODUCTION TO GENETICS § Gregor Mendel § worked with peas § discovered 7 traits in true breeding pea plants § F 1 generation § F 2 generation

INTRODUCTION TO GENETICS § Gene functional unit that controls inherited trait expression that is passed on from one generation to the next § Dominant allele a specific trait that appears in the F 1 generation § Denoted with a capital letter

INTRODUCTION TO GENETICS § Recessive allele a specific trait that is masked in the F 1 generation § Denoted with a small letter § Homozygous organism with two of the same alleles for a specific trait

INTRODUCTION TO GENETICS § Heterozygous organism with two different alleles for a specific trait § Hybrid organism heterozygous for a specific trait

INTRODUCTION TO GENETICS

INTRODUCTION TO GENETICS § Segregation § A process that separates the two alleles § Independent assortment

INTRODUCTION TO GENETICS § Mendel’s principles § individual units, called genes, determine biological characteristics § For each gene, an organism receives one allele from each parent.

INTRODUCTION TO GENETICS § if an organism inherits different alleles for the same trait, one allele may be dominant over the other § some genes segregate independently

INTRODUCTION TO GENETICS § TURN AND TALK Explain dominance, segregation, and independent assortment.

INTRODUCTION TO GENETICS § Meiosis § Chromosomes § Forming gametes § haploid and diploid cells § Haploid having one copy of each chromosome § Diploid having two copies of each chromosome

INTRODUCTION TO GENETICS § Phases of meiosis § Have students reproduce chart on pg 133 of book. § Meiosis and genetic diversity § chromosome combinations (pg 134 in book)

INTRODUCTION TO GENETICS § Crossing over exchange of chromosomal segments between a pair of homologous chromosomes during prophase I

INTRODUCTION TO GENETICS § TURN AND TALK Explain how crossing over increases genetic diversity.

INTRODUCTION TO GENETICS § Analyzing inheritance § Probability and genetics

§ INTRODUCTION TO GENETICS A closer look at heredity § Incomplete dominance complex heritance pattern in which the heterozygous phenotype is intermediate between two heterozygous parents

INTRODUCTION TO GENETICS § Co-dominance complex inheritance pattern that occurs when neither allele is dominant and both alleles are expressed

INTRODUCTION TO GENETICS § Polygenic traits characteristic, such as eye color or skin color, that results from the interaction of multiple gene pairs