Question

x-linked recessive traits
the pedigree below shows an x-linked recessive trait. females that are affected are $x^hx^h$. males that are affected are $x^hy$. determine and write in the genotypes on each of the lines. its ok to leave a \?\ for any chromosome you dont know. shade in carriers half way.
pedigree #11
pedigree #12
pedigree #13

x-linked dominant traits
the pedigree below shows an x-linked dominant trait. females that are affected can either be $x^hx^h$ or $x^hx^h$. males that are affected are $x^hy$. determine and write in the genotypes on each of the lines. its ok to leave a \?\ for any chromosome you dont know.
pedigree #14
pedigree #15
pedigree #16

sex-linked dominant vs. recessive
analyze each pedigree and determine if the inheritance pattern shows an x-linked recessive, x-linked dominant, or both. circle the correct inheritance pattern under each pedigree.
pedigree #17
x-linked recessive
x-linked dominant
both
neither
pedigree #18
x-linked recessive
x-linked dominant
both
neither
pedigree #19
x-linked recessive
x-linked dominant
both
neither
pedigree #20
x-linked recessive
x-linked dominant
both
neither

Explanation:

---

X-Linked Recessive Traits (Pedigrees #11, #12, #13)

Pedigree #11

Step1: Assign father's genotype

Affected male: $X^hY$

Step2: Assign mother's genotype

Unaffected female (carrier, since she has affected children): $X^HX^h$

Step3: Assign son's genotype

Affected male: $X^hY$

Step4: Assign daughter's genotype

Affected female: $X^hX^h$

Pedigree #12

Step1: Assign mother's genotype

Affected female: $X^hX^h$

Step2: Assign father's genotype

Unaffected male: $X^HY$

Step3: Assign son's genotype

Affected male: $X^hY$

Step4: Assign daughter's genotype

Unaffected female (carrier): $X^HX^h$

Pedigree #13

Step1: Assign father's genotype

Affected male: $X^hY$

Step2: Assign mother's genotype

Unaffected female (carrier, since she has affected children): $X^HX^h$

Step3: Assign son 1 genotype

Affected male: $X^hY$

Step4: Assign son 2 genotype

Unaffected male: $X^HY$

Step5: Assign daughter 1 genotype

Affected female: $X^hX^h$

Step6: Assign daughter 2 genotype

Unaffected female (carrier): $X^HX^h$

---

X-Linked Dominant Traits (Pedigrees #14, #15, #16)

Pedigree #14

Step1: Assign mother's genotype

Affected female: $X^HX^h$ (since children are unaffected)

Step2: Assign father's genotype

Unaffected male: $X^hY$

Step3: Assign son's genotype

Affected male: $X^HY$

Step4: Assign daughter's genotype

Unaffected female: $X^hX^h$

Pedigree #15

Step1: Assign mother's genotype

Unaffected female: $X^hX^h$

Step2: Assign father's genotype

Unaffected male: $X^hY$

Step3: Assign son's genotype

Unaffected male: $X^hY$

Step4: Assign daughter's genotype

Unaffected female: $X^hX^h$

Pedigree #16

Step1: Assign father's genotype

Affected male: $X^HY$

Step2: Assign mother's genotype

Unaffected female: $X^hX^h$

Step3: Assign son 1 genotype

Unaffected male: $X^hY$

Step4: Assign son 2 genotype

Unaffected male: $X^hY$

Step5: Assign daughter 1 genotype

Affected female: $X^HX^h$

Step6: Assign daughter 2 genotype

Affected female: $X^HX^h$

---

Sex-Linked Dominant vs. Recessive (Pedigrees #17-#20)

Pedigree #17

Step1: Analyze inheritance pattern

Affected mother passes trait to son; unaffected father cannot pass X-linked recessive to son. This matches X-linked dominant.

Pedigree #18

Step1: Analyze inheritance pattern

Affected mother passes trait to daughter; unaffected father. This matches X-linked dominant (X-linked recessive would require father to be affected for affected daughter).

Pedigree #19

Step1: Analyze inheritance pattern

Affected mother and father have unaffected daughter. X-linked dominant would mean all daughters inherit father's $X^H$, so this cannot be dominant. X-linked recessive: affected mother ($X^hX^h$) and affected father ($X^hY$) would only have affected children, which does not match. So this fits neither.

Pedigree #20

Step1: Analyze inheritance pattern

Unaffected mother and affected father have affected son. X-linked dominant: father would pass $X^H$ to daughters, not sons; X-linked recessive: mother would need to be carrier to pass $X^h$ to son, which is possible. This matches X-linked recessive.

---

Answer:

X-Linked Recessive Genotypes:

1. Pedigree #11

• Mother: $X^HX^h$, Father: $X^hY$
• Son: $X^hY$, Daughter: $X^hX^h$

1. Pedigree #12

• Mother: $X^hX^h$, Father: $X^HY$
• Son: $X^hY$, Daughter: $X^HX^h$

1. Pedigree #13

• Mother: $X^HX^h$, Father: $X^hY$
• Son 1: $X^hY$, Son 2: $X^HY$, Daughter 1: $X^hX^h$, Daughter 2: $X^HX^h$

X-Linked Dominant Genotypes:

1. Pedigree #14

• Mother: $X^HX^h$, Father: $X^hY$
• Son: $X^HY$, Daughter: $X^hX^h$

1. Pedigree #15

• Mother: $X^hX^h$, Father: $X^hY$
• Son: $X^hY$, Daughter: $X^hX^h$

1. Pedigree #16

• Father: $X^HY$, Mother: $X^hX^h$
• Son 1: $X^hY$, Son 2: $X^hY$, Daughter 1: $X^HX^h$, Daughter 2: $X^HX^h$

Sex-Linked Pattern Classification:

1. Pedigree #17: X-Linked Dominant
2. Pedigree #18: X-Linked Dominant
3. Pedigree #19: Neither
4. Pedigree #20: X-Linked Recessive

(Note: For carrier females in X-linked recessive pedigrees, their symbols should be shaded halfway.)