Name: _____________________________
Heredity Part 1: Genetics

_____________________ o 1800’s Austrian monk, mathematician, and scientist
 Began working in the garden at his monastery o _______________________
 His work led to an understanding of how traits are passed from ____________________
 The passing of traits from parents to offspring is called __________________ o Primarily worked with a variety of garden peas
 Noticed several traits that appeared to follow certain patterns of inheritance o Mendel’s Observations
 Mendel mated pea plants together until he got plants that were ___________________

Also known as pure-bred o These are organisms that always pass on ____________________
 Ex. _______ plant that always has _________ offspring
 Once he established 2 true-breeding lines for each trait, he mated them together

For example, true-breeding yellow seed and true breeding green seeds

He noticed that all of the offspring looked like _____ of the parents, but not the other (Ex. All ________, no _________) o Called them ____________ because they got one gene from each parent
 He then ________________ each of the offspring

He noticed that most looked like the parent, but some did not o Mendel’s Hypotheses
 He hypothesized that one of the traits was ____________________ the other
 He called these traits ________________
 Because the other trait was not expressed in the first generation, but reappeared in the second, he hypothesized that the trait was still there, but was being ________________ by the dominant trait.
 He called these traits ________________

o Example of Mendel’s Experiment-Yellow and green seeds
 Mendel developed a true-breeding line of plants with ________ seeds and a truebreeding line of plants with ______ seeds
 He took one __________-seeded plant and one __________-seeded plant and mated them together
 All of the offspring had _________ seeds
 He then took each of these _________ -seeded plants and self-pollinated them
 ______ of the offspring had yellow seeds and ______ had green seeds
 He concluded that yellow was ________________ and green was _________________ o Results of Mendel’s Experiment
 Mendel’s experiments continually showed that ____ of the plants showed the dominant trait and ____ showed the recessive trait

__:__ ratio o Mendel’s Laws of Inheritance
 Law of _______________

For any particular trait, the pair of ____________ from each parent separate and only ____ allele passes from each parent to an offspring o Recall that we have ___________ of chromosomes (one set from mom and one set from dad)
 During meiosis, ___ of these are sorted into each gamete (sex cell)

Which one winds up in each is ___________
 Law of __________________________

Different pairs of alleles for one trait are passed to offspring _____________ of alleles for other traits o Most traits are NOT linked in any way. You could get your mom’s blue eyes without getting her blonde hair, height, etc. o Mendel’s Principle of Dominance
 Traits can be ____________ or _____________
 Dominant alleles mask, or ______________, recessive alleles
 Recessive alleles can only be expressed if the offspring receives _____ of the recessive alleles

Any time a dominant allele is present, it will be _______________


Symbols for alleles o Dominant alleles are represented by _________________________
 Example: A, B, C, D o Recessive alleles are represented by _________________________
 Example: a, b, c, d o The gene is represented by _________________ letter, and dominant and recessive alleles of the gene are shown by whether they are _______________________ o You Try It: Indicate whether the following are dominant or recessive:
 T-
 d-
 P-
 E-
 e-

Homozygous vs Heterozygous o Recall that organisms get 2 alleles-1 from each parent o _______________-2 of the same alleles for a trait
 “Homo” means _________
 Example: ___ or ____
 Can be homozygous dominant (_____) or homozygous recessive (____) o _______________-2 different alleles for a trait
 “Hetero” means _____________
 Example: ____ or tT

Note: The latter is rarely used, but will sometimes be the result in a Punnett
Square o You Try It: Indicate whether the following are heterozygous, homozygous dominant, or homozygous recessive
 TT-
 Tt-
 tT-
 tt-


Punnett Squares o Tool to __________________ of a cross (mating) o Often a 2x2 grid
 Can be larger if including more traits o Couple of different types
 ____________ cross (one trait)
 ____________ cross (2 traits)
 Trihybrid cross (3 traits)-gets too time consuming for this class
 And more that are too complicated to be done by hand and are instead done using
 computers
Using Punnett Squares o Begin by drawing a 2x2 grid o Place one parent’s alleles on top o Place the other parents alleles on the left side
Draw example one here: o Bring ones on the top down o Bring ones on the left across

Practice Problem o A pea plant with genotype Rr is mated with a pea plant with genotype rr. What genotypes could the offspring have?

Genotype and Phenotype o Genotype- The genes (__________) that an organism has
 Geno=gene
 Example: Aa, BB, cc o Phenotype- The expression (_______________) of the genotype
 Ph-Physical
 Example: Green eyes, brown hair, tall

o You Try It: Indicate whether the following are genotypes or phenotypes.
 Aa-
 Blue eyes-
 Rolling tongue-
 TT-
 Principles of heredity o Traits are controlled by ___________ (different versions of a gene) on a chromosome o An allele can be ________________ or _______________________ o When a pair of chromosomes separate during meiosis, the different alleles for a trait move into different _____________________
Use Remaining Room and back of this page for practice Punnett Squares. Make sure to write down the problems.