Chromatin in a Normal CellChromatin in a Normal Cell(one length from each parent)(one length from each parent)

AlleleAllele A version of a geneA version of a gene

DominantDominant Allele that may mask the Allele that may mask the

presence of anotherpresence of another RecessiveRecessive

Allele that may be masked Allele that may be masked by anotherby another

HeterozygousHeterozygous The 2 alleles are differentThe 2 alleles are different

HomozygousHomozygous The 2 alleles are identicalThe 2 alleles are identical

Earlobe GeneEarlobe Gene

Melanin GeneMelanin Gene

Polydactyly GenePolydactyly Gene

FFFreeFree

ffAttachedAttached

aaAlbinoAlbino

aaalbinoalbino

PPExtraExtra

FingersFingers

PPExtraExtraFingersFingers

♂♂ ♀♀

Chromatin in a Normal CellChromatin in a Normal Cell(one length from each parent)(one length from each parent)

GenotypeGenotype The set of alleles an The set of alleles an

organism possessesorganism possesses PhenotypePhenotype

The genetic outcome The genetic outcome resulting from the genotyperesulting from the genotype

Earlobe GeneEarlobe Gene

Melanin GeneMelanin Gene

Polydactyly GenePolydactyly Gene

FFFreeFree

ffattachedattached

aaalbinoalbino

aaalbinoalbino

PPExtraExtra

FingersFingers

PPExtraExtraFingersFingers

♂♂ ♀♀

InheritanceInheritance

F

f

F

f

f

f

F

F

f

f

F

F

Exact copiesExact copies Pure bred parents

What will the F1 offspring look like?

PP x pp p pPP

P p

Phenotype = 100% PurpleGenotype = 100% Heterozygous

What will the F2 offspring look like?

Phenotype = 75% Purple 25% whiteGenotype = 100% Homo. Dominant, 50% Hetero., 25% Homo. Recessive

Dihybrid CrossDihybrid CrossGgYyGgYy

GYGY

PHENOTYPEPHENOTYPE

G-Y- : 9G-Y- : 9

G-yy : 3G-yy : 3

ggY- : 3ggY- : 3

ggyy : 1ggyy : 1

GyGy gYgY gygy

GGYYGGYY GGYyGGYy GgYYGgYY GgYyGgYyGYGY

ggYYggYY

GgYyGgYy GgyyGgyy

GgYYGgYY GgYyGgYy

GGyyGGyy

ggYyggYy

GGYyGGYyGyGy

gYgY

GgYyGgYy GgyyGgyy ggYyggYy ggyyggyygygy

Law of segregation: two Law of segregation: two alleles for a trait separate alleles for a trait separate when gametes are formedwhen gametes are formed

Law of Independent Law of Independent assortment: assortment:

Alleles of different genes Alleles of different genes separate independently of separate independently of one another during one another during gamete formation gamete formation

CodominanceCodominance Both alleles are detectable in a specimenBoth alleles are detectable in a specimen Gene:Gene: Cattle coat colorCattle coat color

AllelesAlleles

CCRR = red= red

CCWW = White= White

GenotypesGenotypes

CCRRCCRR = red coat= red coat

CCWWCCWW = white coat= white coat

CCRRCCWW = roan coat= roan coat

Multiple AllelesMultiple Alleles

More than two alleles exist for a geneMore than two alleles exist for a gene Human Blood TypeHuman Blood Type

IIAA = Type A carbs on RBC surface= Type A carbs on RBC surface IIBB = Type B carbs on RBC surface= Type B carbs on RBC surface ii = Neither type on RBC surface= Neither type on RBC surface

Multiple AllelesMultiple AllelesBlood TypeBlood Type GenotypeGenotype AntibodiesAntibodies

Universal AcceptorUniversal Acceptor

Universal DonorUniversal Donor

Linked Genes Linked Genes

Polygenic DominanceDominance

Brown overBrown over Blue overBlue over

Green Green

Chrom.15 Chrom.19

Sex linked: traits are tied to Sex linked: traits are tied to XX or or Y Y

Xr Y

XR

XR

XR XR

XR XR

Xr

Xr Y

Y

XR Y

Xr

XR XRXR

XRXr Xr

XR Y

Y

Sex linked: traits are tied to Sex linked: traits are tied to XX or or Y Y

Xr Y

XR

XR

XR XR

XR XR

Xr

Xr Y

Y

XR Y

Xr

XR XRXR

XRXr Xr

XR Y

Y

Color blindness:malesRecessive x linked Abnormal production of pigment(protein) Does not absorb red green light

Sex influencedSex influenced Trait not tied to sex chromosomeTrait not tied to sex chromosome

Autosomal chromosome produces protein which Autosomal chromosome produces protein which affects the production of other proteins. affects the production of other proteins.

Testosterone affectsTestosterone affects

the production and the production and

location of hair in males. location of hair in males.

Patterns of Inheritance Patterns of Inheritance

Polygenic: Eye color, skin color, height Polygenic: Eye color, skin color, height

Complex characters: Skin color=sun, Complex characters: Skin color=sun,

Multiple alleles: Blood typeMultiple alleles: Blood type

Incomplete Dominance: Red x White= PinkIncomplete Dominance: Red x White= Pink

X-linked: Color blindness, fruit fly eyesX-linked: Color blindness, fruit fly eyes

Sex influenced: Male pattern baldnessSex influenced: Male pattern baldness

Single alleles: Huntington’s disease, Single alleles: Huntington’s disease,