Guided Notes – Mendelian Genetics

Let’s start with the basics! Offspring share _______________ or characteristics with their parents. Genetics explains how these traits are passed down – through the ___________________. The way chromosomes interact during _______________ (and fertilization) explains the patterns we see in genetics.

Notes: Genetics The “Father of Genetics” is Gregor _________. He used ___________ plants to further his investigations about patterns of heredity. Why pea plants? Easy to __________ which plants were bred together They can self __________________ (reproduce with themselves) Easy to count the offspring with certain ___________ Easy to __________ Produce many _______________ quickly They have “either / or” traits (not in between), the ______________ are dominant or recessive… alleles are different versions of the gene – Ex. Gene: eye color, Alleles: green, blue, brown

Fertilization of Pea Plants ____________ ____________

Mendel’s Experiments Grew pea plants that were _________ for a trait Always produced offspring with that trait The parents were called the ____ generation The offspring of the cross between the P1 generation were called the ____ generation The F1 generation was pollinated with its own pollen (______ ____________) and the offspring that resulted were called the F2 generation

Generations P1 X self

Mendel’s Conclusions… Principle of ________________ Principle of Segregation Principle of _______________ Assortment

Principle of Dominance Have 2 alleles for each gene (an allele is a different version of a _________, ex. Gene = hair color, Allele = brown hair) The ______________ an organism has are called its genotype (you have 2 alleles in a genotype). The physical characteristics of the organism are called its _______________. RULE: When an organism has 2 different alleles for a gene, it only shows the dominant trait in its _______________.

Principle of Segregation Parents have 2 alleles for each trait ___________________ only receive one allele from each parent RULE: A pair of alleles is separated during the formation of ______________ (meiosis)

Principle of Independent Assortment Mendel started looking at more than one trait at a time and he found that the traits did not ______________ (affect) each other He concluded that the alleles for different traits were not inherited ______________ They must mix up randomly during gamete formation (meiosis) RULE: Alleles for different traits are distributed to gametes _________________.

Terminology Homozygous Heterozygous ______________ Recessive “the ___________” Either both dominant or both recessive Heterozygous “different” One ____________ and one _____________ ______________ Always shows up if it is there Recessive Only shows up if there is no ______________ present

Monohybrid Cross _____ box Punnett Square that involves 1 trait. It is used to predict the offspring between ____ parents. Examples: ____________ Ratios (genes, alleles) Phenotypic Ratios (____________ traits)