1. Multiple alleles ( more than 2 alleles for gene in population)
Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example)...
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Transcript of Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example)...
![Page 1: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/1.jpg)
Multiple Alleles• For each trait observed by Mendel….
• Only 2 alleles existed (T & t, for example)
• Many traits are controlled by multiple alleles
• 2 examples include
–Eye color in Drosophila (fruit flies)
–Blood types in humans
![Page 2: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/2.jpg)
Eye Color in Drosophila
• 4 alleles control eye color
• E1 = Wild
• E2 = Apricot
• E3 = Honey
• E4 = White
•E1 > E2 > E3 > E4
![Page 3: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/3.jpg)
Normal Fruit Fly
![Page 4: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/4.jpg)
Mutant Fruit Flies
Short winged fly
Curly winged fly
Normal fruit fly
![Page 5: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/5.jpg)
Eye Color in Drosophila
• Phenotypes Genotypes• Wild Type E1E1, E1E2, E1E3,
E1E4
• Apricot E2E2, E2E3, E2E4
• Honey E3E3, E3E4
• White E4E4
![Page 6: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/6.jpg)
Predict the phenotypic outcome if a honey coloredheterozygous fly is crossed with a white fly!
Phenotypes2 Honey : 2 White
Genotypes2 E3E4 : 2 E4E4
E3 E4
E4
E4
E3E4 E4E4
E3E4 E4E4
![Page 7: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/7.jpg)
What are the possible phenotypes of the parents ina cross which produces the following offspring?
PhenotypesWild & Apricot
GenotpesE1E3 : E2E3
? ?
?
?
E1E2 E1E3
E2E3 E3E3
![Page 8: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/8.jpg)
Possible alleles
C cch
ch
c
Another Example of Multiple Alleles
![Page 9: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/9.jpg)
Antigen type Determines Blood type
Blood Types
![Page 10: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/10.jpg)
A
AAA
A AA
AA
A
Person with blood type AHas antigen
A on RBC’s
&Antibody B
(floating in plasma)
![Page 11: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/11.jpg)
Blood Typing in Humans• Another example of multiple alleles
• Controlled by 3 alleles
• IA, IB and i• IA and IB are said to be codominant
• If a person inherits both of them, then antigen A and antigen B are on the RBC’s
• i is recessive to IA and IB
![Page 12: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/12.jpg)
Antigens A, B or Rh may be present on RBC surface
Blood Components
![Page 13: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/13.jpg)
Genotypes and Phenotypes
for ABO Blood Types• Genotype Phenotype Blood
Type• IAIA, IAi A antigen A
• IBIB, IBi B antigen B
• IAIB A & B antigen AB
• ii neither antigen 0
![Page 14: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/14.jpg)
Predict the phenotypic outcome if a person with blood type AB mates with a person with type O!
Phenotypes1 Type A : 1 Type B
Genotypes2 IAi : 2 IBi
IA IB
i
i
IAi IBi
IAi IBi
![Page 15: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/15.jpg)
Blood Typing Problem 1
MomBlood Type A
BabyBlood Type B
DadUnknown
Blood Type
IAIA orIA i
IBIB or IBi
Must carry
IB__IBIB
IBiIAIB
![Page 16: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/16.jpg)
Blood Typing Problem 1
MomBlood Type B
BabyBlood Type O
DadUnknown
Blood Type
IBIB orIB i
ii
Must carry
i__IBiIAiii
![Page 17: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/17.jpg)
Punnet Squares for Codominance
![Page 18: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/18.jpg)
Calculate the probability of producing a son whois blood type A from the following cross!
Probability of producing a son
= 0.5
Prob. Ofproducing Type A
= 0.5
IA IB
i
i
IAi IBi
IAi IBi
Answer0.5 X 0.5 =
0.25 or25%
MustUse
Product Rule
![Page 19: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/19.jpg)
Blood Typing and Gender• Calculate the probability of producing a
daughter who is blood type A from a cross between a Type B mother and a Type A father, given that each of these individuals have a parent with Type O.
• Since parents are ii, both must be carriers for i
• Mother must be IBi, Father must be IAi
![Page 20: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/20.jpg)
• Prob. of producing Type A = 0.25
• Prob. of producing a daughter = 0.50
• Therefore prob of producing Type A daughter must be found with the product rule……..
• 0.25 ( 0.5) = 0.125 or 1/8 or 13%• Diploma questions ask for answer
rounded to 2 decimal places or to 2 significant digits
![Page 21: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/21.jpg)
Genetics Problem Set
www.biology.arizona
![Page 22: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/22.jpg)
The Product Rule
![Page 23: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/23.jpg)
Incomplete Dominance
Intermediate InheritanceSnapdragons
Red X White = Pink!!
Blending occurs
CodominanceCattle
Red X White = Roan
Both genes expressed
White and red hair present
![Page 24: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/24.jpg)
Red X White = Pink
Gene for red (R) is incompletely dominant to gene for white (W)
![Page 25: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/25.jpg)
Incomplete Dominance: Blending/3 distinct phenotypes
![Page 26: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/26.jpg)
Predict the phenotypic outcome if a Red (RR)snapdragon is crossed with a White (WW) sd!
PhenotypesAll pink!
GenotypesAll RW
R R
W
W
RW RW
RW RW
Capital Lettersused for
both allelessince
they are equally Dominant
![Page 27: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/27.jpg)
Predict the phenotypic outcome if a red (RR)snapdragon is crossed with a pink (RW) sd!
Phenotypes2 Red : 2 pink
Genotypes2 RR : 2 RW
R R
R
W
RR RR
RW RW
![Page 28: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/28.jpg)
Intermediate?Or
Co-dominant?
Askyourself
doesblendingoccur??
![Page 29: Multiple Alleles For each trait observed by Mendel…. Only 2 alleles existed (T & t, for example) Many traits are controlled by multiple alleles 2 examples.](https://reader034.fdocuments.in/reader034/viewer/2022051216/56649eff5503460f94c1527d/html5/thumbnails/29.jpg)
Predict the genotypes of the parents!
Rr & Rr