Pedigree Analysis (Lec 8) Flashcards

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1
Q

What is Hutchinson-Gilford Progeria Syndrome?

A

Inherited as an autosomal dominant trait; children show accelerated aging, hair loss, heart disease - usually die from coronary artery disease

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2
Q

In regards to a pedigree, what is a pro band?

A

the person from whom the pedigree is initiated

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3
Q

Deafness, fair skin, visual problems, and a white forelock are indicative of what ?

A

Wardenburg Syndrome; autosomal dominant

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4
Q

What are some characteristics of an autosomal recessive trait?

A

appears in both sexes with equal frequency; trait tends to skip generations; affected offspring are usually born to unaffected parents; when both parents are heterozygous, approximately 1/4 of the offspring will be affected; appears more frequently among children of consanguineous marriages

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5
Q

What are some characteristics of an autosomal dominant trait?

A

appear in both sexes with equal frequency; both sexes transmit the trait to their offspring; does not skip generations; affected offspring must have an affected parent, unless they possess a new mutation; unaffected parents do not transmit the trait

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6
Q

This disease is an inherited disease in which blood cholesterol is greatly elevated due to a defect in cholesterol transport

A

Familial Hypercholesterolemia

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7
Q

Cholesterol is transported throughout the body in small particles called what?

A

lipoproteins

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8
Q

LDL’s (low-density lipoproteins) are transported to cells and attach to receptors where?

A

on cell membrane

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9
Q

What is defective in familial hypercholesterolemia?

A

the cell membrane receptor

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10
Q

Will only having one defective LDL receptor allele be enough to cause elevated blood cholesterol levels?

A

yes; LDL levels are twice as normal and individuals usually have heart attacks by the age of 35

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11
Q

What are the effects of being homozygous for the defective LDL receptor allele?

A

LDL levels may be 6x normal; may suffer a heart attack by the age of 2 and inevitably by the age of 20

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12
Q

Familial hypercholesterolemia is said to be ____ ____. Homozygotes are rarely seen, and the heterozygous form appears to be inherited as a simple dominant trait

A

incompletely dominant

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13
Q

More males than females affected; affected sons are usually born to unaffected mothers - trait skips generations; approximately 1/2 of a carrier mother’s sons are affected; it is never passed from father to son; all daughters of affected fathers are carriers

The characteristics above describe what type of trait?

A

X-linked recessive

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14
Q

What are some characteristics of an X-linked dominant trait?

A

both males and females are affected; often more females than males are affected; does not skip generations; affected sons must have an affected mother - affected daughters must have either an affected mother or father; affected fathers will pass on the trait to all their daughters; affected mothers (if heterozygous) will pass the trait on to 1/2 of their sons and 1/2 of their daughters

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15
Q

What are some characteristics of a Y-linked trait?

A

only males are affected; it is passed from fathers to sons; it does not skip generations

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16
Q

What is it called when both members of a twin pair express a trait?

A

concordant twins

17
Q

What is it called when only one member of a twin pair expresses a trait?

A

discordant twins

18
Q

define concordance

A

percentage of twin pairs in which both members of the pair express the trait

19
Q

True or false?

genetically influenced traits should exhibit higher concordance in monozygotic twins

A

true

20
Q

Obesity is an example of what type of trait?

A

multifactorial trait

21
Q

The obesity gene in mice produces a protein called what?

A

leptin

22
Q

What does leptin do?

A

decreases appetite by affecting the hypothalamus

23
Q

What are adoption studies used for?

A

to analyze inheritance in humans

similarities between adopted children and their biological parents indicate the importance of genetic factors in expression

similarities between adopted children and their adoptive parents indicate the influence of environmental factors

24
Q

True or false?

Ultrasonography can be used to detect genetic disorders?

A

true

amniotic fluid and a small portion of the chorion can be used for testing

25
Q

What is the method of detection for chromosome abnormalities?

A

examination of a karyotype from cells obtained by amniocentesis or chorionic villus sampling

26
Q

What is the method of detection for cleft lip and palate?

A

ultrasound

27
Q

What is the method of detection for cystic fibrosis?

A

DNA analysis of cells obtained by amniocentesis or chorionic villus sampling

28
Q

What is the method of detection for dwarfism?

A

ultrasound or x-ray

29
Q

What is the method of detection for hemophilia?

A

fetal blood sampling, or What is the method of detection for

30
Q

What is the method of detection for Lesch-Nyhan syndrome?

A

biochemical tests on cell obtained by amniocentesis or chorionic villus sampling

31
Q

What is the method of detection for osteogenesis imperfect?

A

ultrasound or x-ray

32
Q

What is the method of detection for phenylketonuria?

A

DNA analysis on cells obtained by amniocentesis or chorionic villus sampling