Learning Target: Principles of Heredity Part II Learning Target: Principles of Heredity Part II I Can…Correctly use genetic terminology I know I am successful when I can… Define basic hereditary terms Distinguish between dominant and recessive alleles and traits Distinguish between genotype and phenotype I know I am successful when I can… Define basic hereditary terms Distinguish between dominant and recessive alleles and traits Distinguish between genotype and phenotype

Vocabulary terms: Genetics – study of biological inheritance patterns and variation in organisms Trait – distinguishing characteristic that is inherited e.g. earlobe attachment, freckles, hairline pattern Gene – section of DNA that codes for a protein e.g. hemoglobin for RBCs Allele – different versions of a gene e.g. normal or sickle hemoglobin Genetics and Heredity Ch. 6.3 pp Ch. 6.4 pp Ch. 6.3 pp Ch. 6.4 pp

Vocabulary terms: Homozygous – two of the same allele at the same gene locus (location on chromosome) for a trait e.g. Gene trait = earlobe attachment A homozygous individual would have: 2 unattached earlobe alleles or 2 attached earlobe alleles Purebred – genetically uniform Genetics and Heredity

Vocabulary terms: Heterozygous – two different alleles at the same gene locus (location on chromosome) for a trait e.g. Gene trait = earlobe attachment Genetics and Heredity A heterozygous individual would have: 1 unattached earlobe allele and 1 attached earlobe allele Hybrid - NOT genetically uniform

Vocabulary terms: Dominant - allele that is expressed even when 2 different alleles are present e.g. unattached allele is dominant to attached allele in earlobe attachment Genetics and Heredity Heterozygous E e Homozygous E E Designated with an uppercase (capital) letter representing the trait e.g. “E” = Dominant earlobe attachment (unattached)

Vocabulary terms: Recessive - allele that is expressed only when 2 of the same allele are present e.g. attached allele is recessive and will only show if 2 attached alleles are present for earlobes Genetics and Heredity Homozygous attached e e Designated with a lowercase (small) letter representing the trait e.g. “e” = recessive earlobe attachment (attached)

Vocabulary terms: Genotype – Genetic makeup of an organism; actual genes present Homozygous unattached earlobes (E E) Heterozygous unattached earlobes (E e) Homozygous attached earlobes (e e) Genetics and Heredity

Vocabulary terms: Phenotype – physical appearance of trait in organism from expression of allele Unattached earlobes Could be (EE) or (Ee) genotype Phenotype shows Dominate version Attached earlobes Must be (ee) genotype Phenotype of recessive only shows When homozygous recessive genotype Genetics and Heredity

Phenotype – Dominant trait Genotype – Could be either: Homozygous Dominant – e.g. EE Heterozygous – e.g Ee Genetics and Heredity If you know the genotype you will know the phenotype, BUT… If you know the phenotype you cannot know the genotype of a dominant trait without more information If you know the genotype you will know the phenotype, BUT… If you know the phenotype you cannot know the genotype of a dominant trait without more information Phenotype – Reccessive trait Genotype – Must be : Homozygous reccessive – e.g. ee

Vocabulary terms: Genome – all of an organism’s genetic material Human somatic cells have 46 chromosomes in 23 pairs Estimated to contain  25,000 genes Vocabulary terms: Genome – all of an organism’s genetic material Human somatic cells have 46 chromosomes in 23 pairs Estimated to contain  25,000 genes Genetics and Heredity