Name __________________________ Period _____

Guided NotesMendelian Inheritance

_________________________ is the study of ___________________________.

Who is Gregor Mendel? _______________________________________________________________”Principle of ______________________________ – Inheritance of one trait has __________ _______________ on the inheritance of another trait.

Law of ______________________ - suggests that __________ __________ (segregate) during gamete formation.

TraitsGenetics – study of how _____________ are passed from ___________ to ______________ Traits are determined by the _____________________________ on the _______________. A gene is a segment of _________ that determines a _________________________ .

Chromosomes come in pairs, thus __________________________ come in pairs.

Homologous pairs – _________________________________ genes – one from female parent and one from male parent

Example: Humans have 46 chromosomes or ________________ pairs.

One set from dad – 23 in __________ One set from mom – 23 in _________

One pair of Homologous Chromosomes:

_____________________ – different ____________________ (possibilities) for the same _______________________

ex: blue eyes or brown eyes

Name __________________________ Period _____

Dominant and Recessive

Mendel’s second Principle is __________________ – Some alleles are dominant and some are recessiveGene that __________________ the other gene from “showing” – __________________

Gene that ___________ _______ “show” even though it is __________________ – __________________

Symbol – Dominant gene – _______ case letter – ____ Recessive gene – _______ case letter – ____

Example: Straight thumb is _________to hitchhiker thumb ____= straight thumb ____= hitchhikers thumb

(Always use the same letter for the same gene)Straight thumb = TTStraight thumb = TtHitchhikers thumb = tt

Must have ____ recessive __________ for a recessive trait to “________”

Both genes of a pair are the same – __________________ or __________________

TT – homozygous __________________ tt – homozygous __________________

One dominant and one recessive gene – __________________ or __________________

Tt – heterozygous

Genotype and Phenotype

____________________ - the combination of genes an organism has (___________________ _________________ ___________________ )

Ex: TT, Tt, tt

– _________________________ - the __________________________ ______________________________ resulting from genetic make-up Ex: hitchhiker’s thumb or straight thumb ______________ determines the ________________.

Notation of Generations (P, F1, F2)

____ _____________ ___________________ - It is the original pair of plants.____ __________ _________ ______________ - The offspring of the P generation.____ ________ _________ ______________ - The offspring of the F1 generation.

Hitchhiker’s thumb

Name __________________________ Period _____

True Breeding vs Hybrid______ ______________ means the organism has a _______ genotype and will only produce offspring that have the same trait as the parents.

___________ means the organism has been produced by parents that have a two different traits, so ________________ _____________ could been seen in the offspring.

Punnett Squares and Probability

________________________- crosses that involve one trait

Punnett Squares are used to _______________ the ________________ gene makeup of ________________

Example: Black fur (B) is dominant to white fur (b) in mice

1. Cross a heterozygous male with a homozygous recessive female.

Male =_________ X Female= ____________

Write the ratios in the following orders:

Genotypic ratiohomozygous : heterozygous : homozygous dominant recessive

Phenotypic ratio dominant : recessive

Genotypic ratio = 2 _____: 2 _____ 50% Bb : 50% bbPhenotypic ratio = 2 ________ : 2 ________

50% black : 50% whiteCross 2 hybrid mice and give the genotypic ratio and phenotypic ratio.

_________ typic ratio = _____: _____ : _____ 25% BB : 50% Bb : 25% bb

_________ typic ratio = __________: __________ 75% black : 25% white

Name __________________________ Period _____

Example: A man and woman, both with brown eyes (B) marry and have a blue eyed (b) child. What are the genotypes of the man, woman and child?Man = _______________

Woman = _____________

Crosses involving 2 traits – Dihybrid crosses

Example: In rabbits black coat (B) is dominant over brown (b) and straight hair (H) is dominant to curly (h). Cross 2 hybrid rabbits and give the phenotypic ratio for the first generation of offspring.

_____ _____ _____ ______

Possible gametes: _______ X ________

Phenotypes: 9______________ _____3 ______________3 ______________ 1 ______________ _____

_____ _____

Example: In rabbits black coat (B) is dominant over brown (b) and straight hair (H) is dominant to curly (h). Cross a rabbit that is homozygous dominant for both traits with a rabbit that is homozygous dominant for black coat and heterozygous for straight hair. Then give the phenotypic ratio for the first generation of offspring.

Possible gametes (genotypes):

Phenotypes:

Name __________________________ Period _____

Genotypic ratio:

Guided NotesOther Types of Inheritance (Non-Mendelian)

Incomplete Dominance and Codominance

When one allele is NOT completely _____________ over another (they __________ ) – ________ _________ Example: In carnations the color red (R) is incompletely dominant over white (W). The ______color is

______. Give the genotypic and phenotypic ratio from a cross between ______ _________ _________.

_____ X ______

Genotypic = ______ :______ : ______Phenotypic = ______ : ______ : ______

When _________ alleles are _________ - ________________

Example: In certain chickens black feathers are codominant with white feathers.

Heterozygous chickens have black and white speckled feathers.

Name __________________________ Period _____

Name __________________________ Period _____

Sex Determination

• People – ______ chromosomes or _________ pairs

• 22 pairs are ____________________________ (look alike) – called _________________________ – determine body traits

1 pair is the ________________ chromosomes – determines sex (male or female)

• Females – sex chromosomes are ___________ (look alike) – label ________ Males – sex chromosomes are ____________ (different) – label _______

What is the probability of a couple having a boy? Or a girl? Chance of having

female baby? _________male baby? _________

Who determines the sex of the child? ________________

Sex – linked Traits

________________ for these ________________ are located ________________ on the ______ chromosome at the 23rd spot (NOT on the Y chromosome)

X linked alleles ________________ show up in ________________ whether ________________ or ________________ because males have only ____________ X chromosome at the 23rd spot

Examples of ________________ sex-linked disorders:

1. _______________________________ – inability to distinguish between certain colors

2. _____________________________ – blood won’t clot

Name __________________________ Period _____

Why are sex-linked traits like color blindness more common in men?

Example: A female that has normal vision but is a carrier for colorblindness marries a male with normal vision. Give the expected phenotypes of their children. N = normal visionn = colorblindness

Phenotype: ___ _________ __________ __________ ___ _________ __________ __________ ___ _________ __________ __________

Name __________________________ Period _____

Multiple Alleles

__________ _____________ ___________ of the __________ gene that code for a _____________ trait.

In humans, _____ ______ is determined by 3 alleles – ____ , ___ , and ____

BUT each human can only ________ ___ alleles1. Dominant – IA and IB (codominance)

Recessive – ii Type O 2. Blood type – A =IAIA or IAi

B = IBIB or IBi AB = AB O = OO

Example: What would be the possible blood types of children born to a female with type AB blood and a male with type O blood?

_____ X ______

Children would be type _____ or ______only

Name __________________________ Period _____

Guided Notes - Applications of Genetics

Pedigrees________________________ representation of how a __________________ is passed from parents to ___________________________

Tips for making a pedigree

1. ___________________________ are for females

2. ___________________________ are for males

3. _______________ ________________ connecting a male and a female represent a _________

4. _______________ _________________ and ___________________ connect parent to offspring

5. A _________________ circle or square indicates a person _____________________ the trait

6. A circle or square _______________________ ________________________ represents an individual who does NOT have the trait

_______________ shade indicates a _______________ – someone who is _____________________for the trait

Make a pedigree chart for the following couple. Dana is color blind; her husband Jeff is not. They have two boys and two girls. Recall that colorblindness is a recessive sex-linked trait. * Label the pedigree with the generation numbers, person numbers, and genotypes of all individuals.

Name __________________________ Period _____

Polygenic Inheritance______________ ________ - a trait that is controlled by __ or more genes.Examples: height, hair color, eye color, skin color

Gene linkage_________ _______________ - Linked genes sit ___________ _______________ on a chromosome, making them likely to be ______________ together (left). Ex: red hair and freckles

Genes on _____________chromosomes are never linked (center).

Not all genes on the same chromosome are linked. Genes that are __________ ________ from each other are more likely to be _______________ during a process called homologous recombination (right).

Pleiotropy_______________ - when one gene mutation results in ____ or more seemingly ______________observable traits. For example, phenylketonuria (PKU), is characterized by intellectual disabilities and reduced skin and hair pigmentation.

A pleiotropic gene can have an effect on a __________ of traits because the gene ___________ more than one _______________.

Epistasis______________- describes a certain relationship between genes, where an allele of one gene ______ or _________ the visible output, or ___________ , of another gene.

Epistasis is seen in the coat color of Labrador retrievers.

-The _______________allele E determines whether the coat will have dark pigment-Allele B determines how ________ the coat will be.-When a dog has recessive ee alleles, the coat will be _____________.

Name __________________________ Period _____

Goodness of fit - Chi Squared test_____ ____________ (χ2) test - a statistical analysis used to determine if _____________ results are statistically valid when compared to the _______________ results.

It allows us to test for ____________________of observed frequencies from expected frequencies.

Karyotypes detect genetic disorders_______________ - a picture of an individual’s chromosomes. It can be used to _______________ chromosomal _______________ .

○ ________________ - a chromosome that is not directly involved in determining the sex of the individual.

○ _____ ___________ - a chromosome that is directly involved in determining the sex of the individual.

_________ _________________ – (Trisomy 21) 47 chromosomes, extra chromosome at pair #21

Klinefelter’s syndrome – 47 chromosomes, ________ X chromosomes (_______) Boys have low _________________ levels, underdeveloped muscles, sparse facial hair.