Heredity: 5.1-5.6

Heredity: Principles of Inheritance 5.1 1.All living things inherit traits from their _____________. This process is called ____________. parents heredity

Principles of Inheritance 5.1 2. ___________________ (1822-1884) is called the FATHER OF GENETICS because of the pioneering work he did using garden peas to study the inheritance patterns of several traits. Gregor Mendel 3. Mendel concluded that parents pass on distinct factors or traits to their offspring. The units of inherited information (segments of DNA on the chromosome) are called genes.

Mendel’s Laws of Heredity The first law, the law of segregation, states that the two alleles for a trait separate when gametes are formed. The law of independent assortment states that the alleles of different genes separate independently of one another during gamete formation.

Principles of Inheritance 5.1 4. Mendel also concluded that offspring inherit ___ genes for each trait, one from each parent. This is because genes are found on _______________. In sexually reproducing organisms the chromosomes are found in ________ (therefore, so are genes!). Remember: pairs of chromosomes are called homologous chromosomes They pair up during meiosis and separate to form gametes. 2 chromosomes pairs

Principles of Inheritance 5.1 5. The different forms/version of a gene for a trait are called ___________. For example: In guinea pigs there are 2 different forms of their gene for fur color – ________ fur allele and ________ fur allele alleles black brown

Principles of Inheritance 5.1 6. Each offspring inherits one allele (version of a gene) from each parent. An allele for a trait that is ALWAYS expressed when present is called a ___________ allele. An allele for a trait that is hidden/not expressed in the presence of a dominant allele is called a ____________ allele. Example: In guinea pigs ________ fur color is the dominant allele and _________ fur color is recessive. black brown dominant recessive

Attach your first foldable with tape Dominant Traits in humans: Under the flap write Widow’s Peak Tongue rolling Dimples Freckles Recessive Traits in humans: Blonde Hair No Freckles Attached ear lobe Blue eyes Straight Hair Circle the dominant & recessive traits that you have!

Principles of Inheritance 5.1 7. Genes are represented by _________. Dominant = Recessive = letters UPPERCASE (AA) lowercase (aa)

“Physical Appearance” Alleles Draw the two boxes at the top of the third page Genotype Phenotype “Letters” Ex: BB “Physical Appearance” Ex: Black Hair

Principles of Inheritance 5.1 8. An offspring’s pair of alleles for a particular trait inherited by his parents is called a __________ and is represented by ____ letters. Example: In guinea pigs, the possible genotypes for fur color include: ________, ________, ________, _______ 9. The way the genotype is expressed in the physical appearance of an offspring is called that organism’s Phenotype. Example: In guinea pigs, the BB genotype appears as a black fur color phenotype. genotype 2 BB Bb bB bb

10. Complete the following chart: Trait Possible Genotypes Possible Phenotypes Guinea Pig Fur Color BB Black Bb Black bB Black bb brown