Std In sexually reproducing organisms, each offspring contains a mix of characteristics inherited from both parents. D 37. Use the Punnett square technique to predict the distribution of traits in mono- and di-hybrid crossings.

Learning Target: Principles of Heredity Learning Target: Principles of Heredity I Can…Explain the foundation principles of Mendelian Genetics I Will… Briefly describe Mendel’s contribution Describe Mendel’s experimental design Describe Mendel’s conclusions and Law of Segregation Define basic hereditary terms Distinguish between genotype and phenotype I Will… Briefly describe Mendel’s contribution Describe Mendel’s experimental design Describe Mendel’s conclusions and Law of Segregation Define basic hereditary terms Distinguish between genotype and phenotype

All started with Austrian monk Gregor Mendel in the 1800s. Mendel showed that: Traits are inherited as discrete units. Laid groundwork of genetics Demonstrated patterns of inheritance All started with Austrian monk Gregor Mendel in the 1800s. Mendel showed that: Traits are inherited as discrete units. Laid groundwork of genetics Demonstrated patterns of inheritance

Mendel used purebred, self-pollinating pea plants with a selection of “either / or” traits including: Pea shape, pea color, pod shape, pod color, plant height, flower color, and flower position. Mendel used purebred, self-pollinating pea plants with a selection of “either / or” traits including: Pea shape, pea color, pod shape, pod color, plant height, flower color, and flower position.

Mendel’s Experimental Design: Use of self-pollinating pea plants Can control reproduction of plants Reproduce quickly Self-pollination creates genetically “pure” genetic lines “Either / Or” Traits Only two allele versions for each trait studied No blending of traits Dominant v. Recessive Good scientific method (controlled variables and one I.V.) Many trials / reproduced results (validity)_ Mendel’s Experimental Design: Use of self-pollinating pea plants Can control reproduction of plants Reproduce quickly Self-pollination creates genetically “pure” genetic lines “Either / Or” Traits Only two allele versions for each trait studied No blending of traits Dominant v. Recessive Good scientific method (controlled variables and one I.V.) Many trials / reproduced results (validity)_

Mendel’s Experimental Design: Cross – mating of two organisms P 1 – Parental generation F 1 – First Filial (first offspring) generation F 2 – Generation produced from F 1 Cross – mating of two organisms P 1 – Parental generation F 1 – First Filial (first offspring) generation F 2 – Generation produced from F 1

Mendel’s Experimental Design: Cross – mating of two organisms P 1 – Parental generation F 1 – First Filial (first offspring) generation F 2 – Generation produced from F 1 Cross – mating of two organisms P 1 – Parental generation F 1 – First Filial (first offspring) generation F 2 – Generation produced from F 1

Law of Segregation: Organisms donate only one copy of each gene in the gametes (haploid) to their offspring Genes segregate or separate during meiosis Remember the process of meiosis segregates only one of each chromosome into each of the gametes Mendel’s Conclusions

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

Learning Check √: Principles of Heredity Learning Check √: Principles of Heredity Considering Ms. Brown has unattached earlobes and her son has attached earlobes and her daughter has unattached earlobes, What is Ms. Brown’s genotype? ________________ What is Ms. Brown’s son’s genotype? ______________ How did you figure this out? Can you determine Ms. Brown’s daughter’s genotype? Explain Why or Why not. Considering Ms. Brown has unattached earlobes and her son has attached earlobes and her daughter has unattached earlobes, What is Ms. Brown’s genotype? ________________ What is Ms. Brown’s son’s genotype? ______________ How did you figure this out? Can you determine Ms. Brown’s daughter’s genotype? Explain Why or Why not.