Non-Mendelian Genetics Inheritance patterns that are neither dominant nor recessive.
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Transcript of Non-Mendelian Genetics Inheritance patterns that are neither dominant nor recessive.
Non-Mendelian GeneticsNon-Mendelian Genetics
Inheritance patterns that are Inheritance patterns that are neither dominant nor recessiveneither dominant nor recessive
Do Now:Do Now: Take out homework. Take out homework. Then…clear desks.Then…clear desks.
Homework:Homework: finish practice sheets finish practice sheets
Genetics:Genetics: Dihybrid CrossesDihybrid Crosses
BbHh X bbhh (parents)BbHh X bbhh (parents)1.1. What gametes will each parent What gametes will each parent
produce?produce?
2.2. What will be the genotypes of their What will be the genotypes of their offspring?offspring?
3.3. What would be the phenotypes? What would be the phenotypes?
Easter Egg GeneticsEaster Egg Genetics
PP=purplePP=purplepp=pinkpp=pinkPp=orangePp=orangeBB=blueBB=bluebb=yellowbb=yellowBb=greenBb=green
Bp=redBp=redBP=whiteBP=whitePb=yellow spottedPb=yellow spottedbp=white spottedbp=white spottedBlack=genetic Black=genetic
mutation!!!mutation!!!
An egg may be all purple, so it was PP crossed with PP. Or it may be orange and pink, meaning it was Ppxpp.
In In Mendelian genetics (Complete Mendelian genetics (Complete dominance)dominance), there are only two possible , there are only two possible
phenotypes: dominant or recessivephenotypes: dominant or recessive
Tall plant X Short plant = Tall plantTall plant X Short plant = Tall plant
(TT) (tt) (Tt)(TT) (tt) (Tt)
But, not all inheritance is based on the rules of Complete Dominance!!
Other inheritance patterns include:Other inheritance patterns include:
1.1. Incomplete InheritanceIncomplete Inheritance
2.2. CodominanceCodominance
3.3. Multiple AllelesMultiple Alleles
4.4. Polygenic TraitsPolygenic Traits
5.5. Sex-linkedSex-linked
1. Incomplete Inheritance: 1. Incomplete Inheritance: Blending traitsBlending traits
Neither trait is dominantNeither trait is dominantHybrids Hybrids BLENDBLEND to make a to make a
medium phenotypemedium phenotype
Red FlowerRed Flower X White Flower = X White Flower = PinkPink
(RR) (WW) (RW)(RR) (WW) (RW)
Incomplete Inheritance ProblemIncomplete Inheritance Problem
What is the probability of pink flowers if What is the probability of pink flowers if pink flowers are bred with red flowers?pink flowers are bred with red flowers?
50% chance of Pink Flowers
2. CoDominance: 2. CoDominance: Traits show up together as Traits show up together as
spots or stripesspots or stripes
Co = togetherCo = together
Black CowBlack Cow X White Cow = S X White Cow = Sppootttteedd CCooww
(BB) (WW) (BW)(BB) (WW) (BW)
CoDominance ProblemCoDominance Problem
What are all the possible phenotypes What are all the possible phenotypes when two spotted cows are bred?when two spotted cows are bred?
Possible phenotypes are a black
cow, 2 spotted
cows, and a white cow
Below are imaginary organisms. Note horn shape, leg length, fur color and tail shape. Now determine the type of inheritance of the four traits by examining the genotypes of
the parents and offspring.
3. Multiple Alleles: 3. Multiple Alleles: More than 2 More than 2 types of alleles exist for a traittypes of alleles exist for a trait
Rabbits have more than 144 alleles for coat Rabbits have more than 144 alleles for coat color! color!
The same allele can be dominant or
recessive depending on context::agouti > black > albinoagouti > black > albino
What will offspring look like if a What will offspring look like if a heterozygous agouti/black rabbit was heterozygous agouti/black rabbit was crossed with an albino rabbit?crossed with an albino rabbit?
Blood type is determined by Blood type is determined by Multiple alleles and Co-dominanceMultiple alleles and Co-dominance
People have different blood types because of People have different blood types because of different carbohydrates on their surface. different carbohydrates on their surface.
Blood Type Inheritance Rules:Blood Type Inheritance Rules:
1.1. A person with the A person with the IIAA allele will have A allele will have A carbohydrates. carbohydrates.
2.2. A person with the A person with the IIBB allele will have B allele will have B carbohydrates.carbohydrates.
3.3. A person with the A person with the recessive i allele will have no recessive i allele will have no carbohydratescarbohydrates..
4.4. Or a person with Or a person with both Iboth IAA and I and IBB alleles will have alleles will have both A and B carbohydrates both A and B carbohydrates on their cells.on their cells.
Blood Type ProblemsBlood Type Problems
If a woman with AB blood has children with a man who has type O, what will be the possible genotypes of their children? What will be their blood types?
IA IB
ii
IA iIA i
IB iIB i
Cells Genotypes Blood types
IAi, IAIA Type A blood
IBi, IBIB Type B blood
IAIB Type AB blood
ii Type O blood
Ever wonder why there are Ever wonder why there are ranges of skin colors, or eye ranges of skin colors, or eye
colors, or hair colors, or height?colors, or hair colors, or height?
4. Polygenic Traits: Require the 4. Polygenic Traits: Require the interpretation of many genesinterpretation of many genes
Parents:
Ll Mm Nn X Ll Mm NnLl Mm Nn X Ll Mm Nn
This also explains why a couple with This also explains why a couple with heterozygous genes heterozygous genes can have children can have children who look so different.who look so different.
This child received mostly dominant genes
This child received mostly recessive genes
Why are some traits like color-Why are some traits like color-blindness, ALD and hemophilia blindness, ALD and hemophilia
found mostly in boys?found mostly in boys?
5. Sex-linked: genes are found 5. Sex-linked: genes are found on the sex chromosomes (X or on the sex chromosomes (X or
Y)Y)Most of these traits are Most of these traits are recessiverecessive, the , the normal gene is dominantnormal gene is dominant
Sex-linked inheritance rulesSex-linked inheritance rules
Heterozygous Females (XXHeterozygous Females (XXcc) ) are are carrierscarriers. . They do not show the trait, but carry a They do not show the trait, but carry a gene for the traitgene for the trait..
Homozygous Females (XHomozygous Females (XccXXcc) ) have the traithave the traitMales with the gene (XMales with the gene (XccY) Y) have the traithave the trait.—.—
They do not have another X to They do not have another X to counterbalance the affected genecounterbalance the affected gene
If a heterozgous woman with normal vision has children with a man who is colorblind, what are the chances that their children will be colorblind? Will any children be carriers of the trait?
Y
XcY
XY
Xc Y
Xc
X
XcXc
XXc
XcY
XY