11.1 PEDIGREE PRACTICE (2)
NAME_________________________HR___
PEDIGREE BASICS:
-A pedigree is used to analyze genetic inheritance of certain traits, especially disorders and diseases
-Each generation is labeled with a Roman numeral-LABEL each generation on the following pedigrees before starting
-Siblings are placed in birth order from left to right and labeled with number
-AFFECTED female/male
UNAFFECTED female /male
-CARRIER half-shaded circle/square -- IF SHOWN [carrier not always designated]
PEDIGREE A
 Use the pedigree chart to complete the information about muscle twitching.
-Fast-twitch muscles (T) slow-twitch muscles (t)
 LABEL each individual’s genotype below their number symbol [use T__ if could be TT or Tt].
1-CLASSIFY this trait as: recessive or dominant
1-IDENTIFY the genotype of individual #3 _____ and #4 _____
2-DETERMINE if individual #8 is homozygous/heterozygous: homozygous or heterozygous
3-EXPLAIN the relationship between individuals #2 and #12: _____________________ & ___________________
PEDIGREE B
 Use the pedigree chart to complete the information about eye color.
-Brown eyes (B) are not shaded, blues eyes (b) are shaded [eye color is NOT a sex linked trait].
 LABEL each individual’s genotype below their number symbol.
1-Are brown eyes dominant or recessive?
2-What is the probability that one of the offspring of individuals #3 and 4 would have blue eyes?
SHOW the possible genotypes of the offspring using the punnett square.
3-How would you name individuals #8 and 9 who have brown eyes?
homozygous dominant
homozygous recessive
heterozygous
PEDIGREE C
 Use the pedigree chart to complete the information about color-blindnes [color-blindness is a sex-linked trait].
Denote sex chromosomes with the color-blind allele attached [XBXB / XBXb / XBXb / XBY / XbY].
1-IDENTIFY the genotypes of the following individuals:
I-2: __________
II-6: __________
II-8: __________
III-13: __________
III-15: __________
2-How many males have color-blindness? _____ How many females have color-blindness? _____
3-How would you name the 2 females that have color-blindness?
homozygous dominant
homozygous recessive
heterozygous
4-Name two individuals that were carriers of color-blindness (these have purposely not been half-shaded) _____ & _____
PEDIGREE D
 Use the pedigree chart to complete the information about hemophilia. [Hemophilia is a sex-linked recessive genetic
disorder.] Denote the sex chromosomes with the hemophilia allele attached [XNXN / XNXn / XnXn / XNY / XnY]
 LABEL genotypes of the individuals that show the disorder below their number symbol.
1-Which sex can be carriers of hemophilia and not have it? male female
2-Why does II-5 have hemophilia?
3-Why do all daughters in generation II carry the hemophilia gene?
4-Name two III generation hemophilia males-
_____ and _____
5-What is the probability that if #7 & 8 have another child it will be a girl with hemophilia?
Use the punnett square to show the offspring possibilities.
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