Genotype, Phenotype And Inheritance Flashcards

1
Q

What is meant by genotype?

A

An organisms genotype is the set of genes that it carries

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2
Q

What is meant by phenotype?

A

The observable characteristics of an organism

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3
Q

What is genetics the study of?

A

Inheritance and variation

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4
Q

How many alleles of a particular gene does each individual have?

A

2

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5
Q

What is the meaning of homozygous?

A

Two alleles of a gene are the same

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6
Q

What is the meaning of heterozygous?

A

Two alleles of a gene are different

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7
Q

What is the meaning of hemizygous?

A

Only one allele of a gene on the X chromosome (so males only)

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8
Q

Which alleles are dominant in terms of blood type?

A

Allele A dominant over O
Allele B dominant over O
Allele A and B are co dominant

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9
Q

How would you identify an autosomal recessive trait?

A

Heterozygotes unaffected

Males and females equally affected

Can skip generations, seems to come out of nowhere

Both parents of affected individual are heterozygous carriers

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10
Q

How would you identify an autosomal dominant trait?

A

Heterozygotes affected

Males and females equally affected

Rarely found in homozygous state

Every affected individual has at least one affected parent, cannot skip generations

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11
Q

What is an example of an autosomal recessive disease?

A

Cystic fibrosis

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12
Q

What is an example of an autosomal dominant disease?

A

Huntingtons disease

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13
Q

How do you identify an X linked recessive trait?

A

Males and females unequally affected

Every affected male has at least a carrier mother

Every affected female has affected father and carrier mother

Affected males have at least carrier daughters

Affected males cannot give trait to sons

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14
Q

What is an example of an X linked recessive disease?

A

Haemophilia

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15
Q

How is albinism inherited?

A

Recessive

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16
Q

How many genes does each huma have?

A

25,000

17
Q

What is the percentage of two heterozygotes having affected offspring?

A

25%

18
Q

How is Huntington’s disease inherited?

A

Autosomal dominant

19
Q

How is Cystic Fibrosis inherited?

A

Autosomal recessive

20
Q

How is Haemophilia A inherited?

A

X-linked recessive

21
Q

Why are X-linked diseases more common in males?

A

Only need one copy of X chromosome to be affected while females need two

22
Q

Why can’t affected males of X-linked conditions give the trait to their sons?

A

Father can only give Y chromosome to offspring

23
Q

True or Flase:

With X-linked conditions, every affected male will have at least a heterozygous mother.

A

True!

24
Q

Will the daughters of men with X linked conditions be, at least, carriers?

A

Yes

25
Q

What is an example of an X linked dominant condition?

A

X-linked hypophosphatemia (type of rickets)

26
Q

What is an example of a Y-linked condition? (very rare)

A

Retinitis Pigmentosa (night blindness)

27
Q

What are genes on the same chromosome said to be?

A

Linked

28
Q

What do linked genes not show?

A

Independent assortment at meiosis

29
Q

What is recombination frequency between two linked genes dependent on?

A

The distance between the genes

30
Q

What can be used to calculate allelic frequencies and therefore ratios of frequencies in a population?

A

Hardy-Weinberg principle