Mendelian Genetics Mendelian Genetics Gregor Mendel Father of

Mendelian Genetics

Mendelian Genetics • Gregor Mendel – “Father of Genetics” – Austrian Monk who conducted studies on the inheritance of traits in pea plants and described 3 basic laws of genetics.

Mendelian Genetics • Genetics – The study of heredity. • Heredity – The passage of traits from parents to offspring

Mendelian Genetics • Traits - Specific characteristics that vary from one individual to another • Genes – sequences of DNA on a chromosome that determine traits. • Alleles – Alternate forms of the same gene, both located at the same place on homologous chromosomes (one from mom and one from dad)

Mendelian Genetics • Phenotype – the physical characteristics of an organism – observable (red flowers vs white flowers. • Genotype – the genetic makeup of an organism – not observable (the DNA)

Mendelian Genetics • Homozygous – homologous chromosomes have the same alleles – Ex. Both dominant (AA) or both recessive (aa) • Heterozygous – homologous chromosomes have different allelles – Ex. One dominant and one recessive (Aa)

Mendel’s Laws • Law of Dominance – One allele for a trait will be dominant over another. • Dominant – allele that is expressed and hides the presence of other alleles • Recessive – allele that is hidden and only expressed when two are present (must get one from mom AND dad)

Mendel’s Laws • Law of Segregation – During meiosis, alleles for one trait separate and each ends up in a different gamete • Law of Independent Assortment – The distribution of one set of alleles has no influence on other sets of alleles

Mendelian Genetics • Monohybrid Cross – a study involving one gene, trait, or allele • Dihybrid Cross – a study involving two genes, traits, or alleles • P generation – the initial parents in a study • F 1 generation – the offspring that result from the parent generation • F 2 generation – the offspring that result from an F 1 pairing.

Mendelian Genetics • Selective Breeding – the breeding of choice organisms by man to achieve desired traits – Example – domestication of animals and plants

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