pedigreeANALYSIS E X E R C I S E

Biology 3 Kawashima

General Notes

• Each set of slides will show a specific inheritance pattern

• The pedigrees are independent for every new inheritance pattern.

• The first slide of each set will show parental genotypes. Try to figure out the genotypes of the succeeding generations

• Answers and explanations are revealed in succeeding slide. NOTE: Answers revealed may not be the only set of correct answers.

START E X E R C I S E

Biology 3 Kawashima

AutosomalDominant

1 2

4 53

7

6

8

AA aa

AutosomalDominant

• Presence of even one dominant allele A gives the phenotype

• F1 only has one possible genotype Aa

• Crossing 3 and 4 may give either Aa|aa, but as 7 is unaffected, it must be aa

1 2

4 53

7

6

8

AA aa

Aa Aa aaaa

aa Aa

AutosomalDominant

• Crossing 5 and 6 may give either Aa|aa, but as 7 is affected, it must be Aa

• NOT sex-limited because it occurs in both sexes.

• NOT sex-influenced because the heterozygous genotype is expressed in the same way by both sexes (see 4 and 5)

1 2

4 53

7

6

8

AA aa

Aa Aa aaaa

aa Aa

AutosomalDominant

• NOT X-linked dominant nor recessive, if so 7 should also express the phenotype

• NOT Y-linked as it is also observed in females

1 2

4 53

7

6

8

AA aa

Aa Aa aaaa

aa Aa

AutosomalRecessive

1 2

4 53

7

6

aa AA

8

AutosomalRecessive

• Presence of two alleles aa gives the phenotype

• Presence of only one allele a will not exhibit the phenotype

• F1 only has one possible genotype Aa

• Crossing 3 and 4 may give either Aa|aa, but as 7 is unaffected, it must be Aa

1 2

4 53

7

6

aa AA

Aa Aaaa

Aa aa

Aa

8

AutosomalRecessive

• Crossing 5 and 6 may give AA|Aa|aa, but as 7 is affected, it must be only aa

• NOT sex-limited because it occurs in both sexes.

• NOT sex-influenced because the heterozygous genotype is expressed in the same way by both sexes (see 4 and 5)

1 2

4 53

7

6

aa AA

Aa Aaaa

Aa aa

Aa

8

AutosomalRecessive

• NOT X-linked dominant nor recessive, if so 5 (which is a carrier) crossed with 6, it is not possible for 8 to express the phenotype

• NOT Y-linked as it is also observed in females

1 2

4 53

7

6

aa AA

Aa Aaaa

Aa aa

Aa

8

AutosomalDominant Sex-Limited

1 2

4 53

7

6

8 9 10

AA aa

AutosomalDominant Sex-Limited

• Phenotype is male-limited• Presence of even one

dominant allele A in males gives the phenotype

• Females are not affected regardless of genotype

• F1 only has 1 possible genotype Aa

• Crossing 3 and 4 may give either Aa|aa, but either way 7 is unaffected because it is male-limited

1 2

4 53

7

6

8

AA aa

Aa AaAA

AA Aa

aa

9

Aa

10

aa

AutosomalDominant Sex-Limited

• Crossing 5 and 6 may give either Aa|aa, but as 8 is affected, it must be Aa

• Phenotype of 9 does not matter because it is male-limited

• Genotype of 10 is aa because it is an unaffected male

1 2

4 53

7

6

8

AA aa

Aa AaAA

AA Aa

aa

9

Aa

10

aa

AutosomalDominant Sex-Limited

• NOT simple dominance| recessiveness because females do not express the phenotype at all

• NOT sex-influenced. Though genders show different phenotypes for the same genotype, one sex (females in this case) are unaffected whatever the genotype (see 7)

1 2

4 53

7

6

8

AA aa

Aa AaAA

AA Aa

aa

9

Aa

10

aa

AutosomalDominant Sex-Limited

• NOT X-linked dominant|recessive because it is not observed in females.

• NOT Y-linked, if so 8 should not be affected as his father isn’t

1 2

4 53

7

6

8

AA aa

Aa AaAA

AA Aa

aa

9

Aa

10

aa

AutosomalRecessive Sex-Limited

1 2

4 53

7

6

8 9 10

aa AA

AutosomalRecessive Sex-Limited

• Phenotype is male-limited• Presence of both alleles aa

in males gives the phenotype

• Presence of only one allele a will not exhibit the phenotype

• Females are not affected regardless of genotype

• F1 only has 1 possible genotype Aa

1 2

4 53

7

6

8 9 10

aa AA

Aa AaAA

AA aa

Aa

Aa aa

AutosomalRecessive Sex-Limited

• Crossing 3 and 4 may give either Aa|aa, but either way 7 is unaffected because it is male-limited

• Crossing 5 and 6 may give AA|Aa|aa. Since 8 and 10 are affected, they are aa. 7 is unaffected regardless of genotype because it is male-limited

1 2

4 53

7

6

8 9 10

aa AA

Aa AaAA

AA aa

Aa

Aa aa

AutosomalRecessive Sex-Limited

• NOT simple dominance| recessiveness because females do not express the phenotype at all

• NOT sex-influenced because the heterozygous genotype is expressed in the same way by both sexes (see 4 and 5)

1 2

4 53

7

6

8 9 10

aa AA

Aa AaAA

AA aa

Aa

Aa aa

AutosomalRecessive Sex-Limited

• NOT X-linked dominant|recessive because it is not observed in females.

• NOT Y-linked, if so 4 should be affected

1 2

4 53

7

6

8 9 10

aa AA

Aa AaAA

AA aa

Aa

Aa aa

Autosomal Sex-Influenced

1 2

4 53

7

6

8 9 10

AA aa

Autosomal Sex-Influenced

• Phenotype expression changes between males and females.

• For this example, trait is dominant in males while recessive in females.

• In males, one allele A elicits the trait while in females, homozygous allele A is required for expression

1 2

4 53

7

6

8 9 10

AA aa

Aa AaAa

AA aa

aa

Aa Aa

Autosomal Sex-Influenced

• Heterozygote males and females express different phenotypes (see 4 and 5)

• Crossing 3 and 4 may give AA|Aa|aa, but as 7 is an affected female, it must be AA

• Crossing 5 and 6 may give Aa|aa. If 8 is an unaffected male, it must be aa while 9 being an unaffected female, she could be Aa or aa.

1 2

4 53

7

6

8 9 10

AA aa

Aa AaAa

AA aa

aa

Aa Aa

Autosomal Sex-Influenced

• Since 10 is an affected male, he can only be Aa

• NOT simple dominance| recessiveness because heterozygote males and females express different phenotypes.

• NOT sex-limited because it occurs in both sexes.

1 2

4 53

7

6

8 9 10

AA aa

Aa AaAa

AA aa

aa

Aa Aa

Autosomal Sex-Influenced

• NOT likely to be X-linked dominant nor recessive

• NOT Y-linked as it is also observed in females

1 2

4 53

7

6

8 9 10

AA aa

Aa AaAa

AA aa

aa

Aa Aa

X-Dominant Sex-Linked

1 2

4 53

7

6

8 9 10

XAY XX

X-Dominant Sex-Linked

• Alleles are found on the X chromosome

• Males with an XA chromosome always expresses the phenotype as he only can only have one X chromosome, thus only one copy (called hemizygous)

1 2

4 53

7

6

8 9 10

XAY XX

XY XAXXAX

XAX XAY

XY

XAX XY

X-Dominant Sex-Linked

• The X chromosome of males always come from their mother

• A male with a heterozygous affected mother has a ½ chance of also having the phenotype.

• A male with a homozygous affected mother will always have the phenotype.

1 2

4 53

7

6

8 9 10

XAY XX

XY XAXXAX

XAX XAY

XY

XAX XY

X-Dominant Sex-Linked

• A female with an affected father will always show the phenotype

• NOT simple dominance| recessiveness if parents are homozygotes. If this is not given/assumed it is indistinguishable.

• NOT sex-limited because it occurs in both sexes.

1 2

4 53

7

6

8 9 10

XAY XX

XY XAXXAX

XAX XAY

XY

XAX XY

X-Dominant Sex-Linked

• NOT sex-influenced. If pattern is dominant in males, recessive in females (or other way around), the pedigree is inconsistent

• NOT Y-linked because it is observed in females

1 2

4 53

7

6

8 9 10

XAY XX

XY XAXXAX

XAX XAY

XY

XAX XY

X-Recessive Sex-Linked

1 2

4 53

7

6

8 9 10

XaY XX

X-Recessive Sex-Linked

• Alleles are found on the X chromosome

• Males with an XA chromosome always expresses the phenotype as he only can only have one X chromosome, thus only one copy (called hemizygous)

1 2

4 53

7

6

8 9 10

XaY XX

XY XaXXaXa

XaX XaY

XY

XX XY

X-Recessive Sex-Linked

• The X chromosome of males always come from their mother

• A male with an affected mother will always also show the phenotype.

• A female with an affected father may or may not have the same phenotype

1 2

4 53

7

6

8 9 10

XaY XX

XY XaXXaXa

XaX XaY

XY

XX XY

X-Recessive Sex-Linked

• NOT simple dominance| recessiveness if parents are homozygotes. If this is not given/assumed it is indistinguishable.

• NOT sex-limited because it occurs in both sexes.

• NOT sex-influenced if parents are homozygotes. If not, it is indistinguishable.

• NOT Y-linked because it is observed in females

1 2

4 53

7

6

8 9 10

XaY XX

XY XaXXaXa

XaX XaY

XY

XX XY

Y Sex-Linked

1 2

4 53 6

8 9 10

XY* XX

8

Y Sex-Linked

• Allele is found on the Y chromosome

• Only males have a Y chromosome and are the only ones with a chance of expressing the trait. This is called a HOLANDRIC trait.

• NOT simple dominance| recessiveness

1 2

4 53 6

8 9 10

XY* XX

XY* XXXX

XY* XY

XY

XX XY

8

Y Sex-Linked

• NOT sex-limited because all males with an affected father will always express the trait.

• NOT sex-influenced as it is never expressed in females.

• NOT X-linked because it is not observed in females

1 2

4 53 6

8 9 10

XY* XX

XY* XXXX

XY* XY

XY

XX XY

8