Pedigree Analysis

Question 1

genetic representation that depicts the family tree or biological relationship between individuals of the new generation and their ancestors

entails information about genetic disorders in the family history

helps in studying different patterns of inheritance and genetic traits of different individuals

an analytical method, displaying data on the heredity of traits and disorders

uses specific symbols to represent the type of individuals and their relationship with each other

Answer 1

Pedigree analysis

Question 2

Types of pedigree analysis

Answer 2

Autosomal Dominant
Autosomal Recessive
X-linked Recessive
X-linked Dominant
Y-linked

Question 3

Type of Pedigree Analysis:

• Males and females get affected in the same
  ratio.
• The genetic traits express themselves in
  each generation or never skips a generation.
• Two affected parents can produce an
  unaffected child.
• Unaffected parents produce unaffected
  offspring.
• Heterozygotes are also affected.

Answer 3

Autosomal Dominant Pedigree

Question 4

Type of Pedigree Analysis:

• Males and females are affected in the same
  ratio.
• The genetic trait may skip a generation.
• Two affected parents will only produce affected
  children.
• Unaffected parents may produce affected
  offspring since they are carriers or
  heterozygotes.
• Heterozygotes have a normal phenotype.

Answer 4

Autosomal Recessive Pedigree

Question 5

Type of Pedigree Analysis:

• Both males and females are likely to be
  affected.
• The genetic traits may skip a generation.
• The affected father can transfer the
  disease to all female individuals.
• Male to male disease transmission does
  not occur.

Answer 5

X-linked Dominant Pedigree

Question 6

Type of Pedigree Analysis:

• Males are relatively more affected than
  females.
• The genetic trait never skips a generation.
• Only the affected mother can transfer the
  disease to the male individuals.
• Disease transmission from a father to a son
  will not occur.

Answer 6

X-linked Recessive Pedigree

Question 7

Type of Pedigree Analysis:

• Only males are affected.
• Y-chromosome carries the genetic trait.
• Disease transmission occurs from a
  father to a son.

Answer 7

Y-linked Recessive Pedigree

Question 8

Insensitivity to green light

Answer 8

Color blindness, deutan type

Question 9

Insensitivity to red light

Answer 9

Color blindness, protan type

Question 10

Deficiency of galactosidase A; heart and kidney defects, early death

Answer 10

Fabry’s disease

Question 11

Deficiency of glucose-6-phosphate dehydrogenase; severe anemic reaction following the intake of primaquines in drugs and certain foods, including fava beans

Answer 11

G-6-PD deficiency

Question 12

Classic form of clotting deficiency; deficiency of clotting factor VIII

Answer 12

Hemophilia A

Question 13

Christmas disease; deficiency of clotting factor IX

Answer 13

Hemophilia B

Question 14

Mucopolysaccharide storage disease resulting from iduronate sulfate enzyme deficiency; short stature, claw-like fingers, coarse facial features, slow mental deterioration, and deafness

Answer 14

Hunter syndrome

Question 15

Deficiency of steroid sulfatase enzyme; scaly dry skin, particularly on extremities

Answer 15

Ichthyosis

Question 16

Deficiency of hypoxanthine-guanine phosphoribosyltransferase enzyme (HPRT) leading to motor and mental retardation, self-mutilation, and early death

Answer 16

Lesch-Nyhan syndrome

Question 17

Progressive, life-shortening disorder characterized by muscle degeneration and weakness; sometimes associated with mental retardation; deficiency of the protein dystrophin

Answer 17

Duschenne Muscular Dystrophy

Question 18

Examples of diseases under Autosomal Dominant

Answer 18

Polydactyly
Huntington’s Disease

Question 19

Diseases under Autosomal Recessive

Answer 19

Cystic fibrosis
Tay-Sach’s Disease

Question 20

Diseases under Sex-linked Recessive

Answer 20

Color-blindness
Duschenne Muscular Dystrophy

Question 21

every affected individual has an affected parent, and normal parents have only normal progeny.

female offspring of affected males are all affected, but no sons are affected.

affected females produce both affected sons and affected daughters.

Answer 21

X-linked Dominant

Question 22

It is _________ because affected individuals do not necessarily have an affected parent (remember, 100 percent penetrance).

It is _________ because all but one of the affected individuals is a male, apparently coming from a carrier Aa mother.

Answer 22

sex-linked recessive

Question 23

None of the sons would express the trait, because a sex-linked trait can be passed only to daughters by a male parent.

All of the daughters would have the condition, as they would all receive one of their X chromosomes from their father.

Answer 23

X-linked Dominant

Question 24

100% of the male children would have the marker inherited from their affected father.
None of the daughters would have the marker

Answer 24

Holandric transmission