2 traits with dominance (pp 185-186) identify alleles (letters) identify alleles (letters) write out...
TRANSCRIPT
2 Traits With Dominance 2 Traits With Dominance (pp 185-186)(pp 185-186)
Identify alleles Identify alleles (letters)(letters)
Write out crossWrite out cross Set up Punnett SquareSet up Punnett Square
4 possible gametes for 4 possible gametes for each parenteach parent
16 square Punnett 16 square Punnett SquareSquare
Fill in Punnett SquareFill in Punnett Square Give ResultsGive Results
Set C- 2 Traits With Set C- 2 Traits With DominanceDominance
T=Tall, t=ShortT=Tall, t=Short R=Round, R=Round,
r=Wrinkledr=Wrinkled TtRr x TtRrTtRr x TtRr Possible gametesPossible gametes
Male- Male- TR, Tr, tR, trTR, Tr, tR, tr
Female- Female- TR, Tr, tR, trTR, Tr, tR, tr
TR Tr tR tr
TR
Tr
tR
tr
Set C- 2 Traits With Set C- 2 Traits With DominanceDominance
TtRr x TtRrTtRr x TtRr Pheno-Pheno-
9 Tall Round9 Tall Round 3 Tall Wrinkled3 Tall Wrinkled 3 Short Round3 Short Round 1 Short Wrinkled1 Short Wrinkled
This is a dihybrid cross This is a dihybrid cross (hybrid for 2 traits)(hybrid for 2 traits)
Phenotype will always Phenotype will always be 9:3:3:1be 9:3:3:1
TR Tr tR tr
TR TTRR TTRr TtRR TtRr
Tr TTRr TTrr TtRr Ttrr
tR TtRR TtRr ttRR ttRr
tr TtRr Ttrr ttRr ttrr
Set D- Incomplete Dominance Set D- Incomplete Dominance p 184 p 184
Neither allele dominates Neither allele dominates otherother
White x White = WhiteWhite x White = White Red x Red = RedRed x Red = Red White x Red = PinkWhite x Red = Pink Offspring is a mix of 2 Offspring is a mix of 2
traitstraits Phenotype will be the Phenotype will be the
same as the Genotypesame as the Genotype RR = redRR = red rr = whiterr = white Rr = pinkRr = pink
Codominance p 184Codominance p 184
Both alleles are Both alleles are expressedexpressed
BB = blackBB = black WW = whiteWW = white BW = black & whiteBW = black & white Black feathers x Black feathers x
white feathers = white feathers = black and white black and white feathersfeathers
Set E- Sex DeterminationSet E- Sex Determination
Sex ChromosomesSex Chromosomes Determines sexDetermines sex X & Y chromosomesX & Y chromosomes Males = XYMales = XY Females = XXFemales = XX Humans = 2 (1 pair)Humans = 2 (1 pair)
AutosomesAutosomes All other chromosomesAll other chromosomes Humans = 44 (22 pair)Humans = 44 (22 pair)
Karyotype- shows Karyotype- shows chromosomes (see chromosomes (see page 236) page 236)
Set F- Sex Linked TraitsSet F- Sex Linked Traits
Determined by Determined by recessive alleles recessive alleles located on the “X” located on the “X” chromosomechromosome
Occur more often Occur more often in males (need only in males (need only 1 recessive allele)1 recessive allele)
Ex. male = XEx. male = XnnY Y Ex. female = XEx. female = XnnXXnn
Set F- Sex Linked TraitsSet F- Sex Linked Traits
Possible genotypesPossible genotypes Normal Male = XNormal Male = XNNYY Male with trait = XMale with trait = XnnYY Normal Female = XNormal Female = XN N XXNN
Carrier Female = XCarrier Female = XNNXXnn
Female with trait = XFemale with trait = XnnXXnn
Set G- Multiple AllelesSet G- Multiple Alleles
More than 2 alleles for a More than 2 alleles for a trait (in the populations trait (in the populations gene pool)gene pool)
Each individual will still Each individual will still have only 2 alleles for the have only 2 alleles for the traittrait C = full colorC = full color h = himalayanh = himalayan a = albinoa = albino
Example- some rabbitsExample- some rabbits CC, Ch, or Ca = full colorCC, Ch, or Ca = full color hh, ha = himalayanhh, ha = himalayan aa = albinoaa = albino
Set H- Human Blood TypeSet H- Human Blood Type
Multiple allelesMultiple alleles A, B, OA, B, O
DominanceDominance A & B dominant to A & B dominant to
O O CodominanceCodominance
A & B codominant A & B codominant to each otherto each other
Set H- Human Blood TypeSet H- Human Blood Type
TypeType GenotypeGenotype AA
AA, AOAA, AO BB
BB, BOBB, BO ABAB
ABAB OO
OOOO
Genetic DisordersGenetic Disorders
Huntington disease-Huntington disease- Caused by a single Caused by a single
dominant allele (H)dominant allele (H) Sickle cell anemia-Sickle cell anemia-
Autosomal recessiveAutosomal recessive Colorblindness (red–Colorblindness (red–
green)-green)- Sex linked trait, recessive Sex linked trait, recessive
allele on X chromosomeallele on X chromosome
Genetic DisordersGenetic Disorders
Hemophilia-Hemophilia- Sex linked trait, recessive Sex linked trait, recessive
allele on X chromosomeallele on X chromosome Down syndrome-Down syndrome-
Nondisjunction of 21Nondisjunction of 21stst pair pair of chromosomesof chromosomes
No disjunction- failure No disjunction- failure of chromosomes to of chromosomes to separate during separate during meiosismeiosis