Review - Genetics and Modes of Gene action Flashcards

1
Q

In terms of breeding, how do you define a gene?

A

Basic unit of heredity.

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2
Q

A chromosome is:

A

A long strand of DNA and associated proteins present in the nucleus of all cells.

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3
Q

Chromosomes are found in ________ in all animals.

A

pairs

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4
Q

Locus (singular)/loci (plural) is a site of a particular region/gene on a __________.

A

Chromosome

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5
Q

An allele is:

A

an alternative form of a gene.

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6
Q

Epistasis is:

A

How one gene is affecting the expression of another gene.

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7
Q

What are the five types of gene action/dominance?

A
  • Partial dominance
  • Codominance
  • Complete dominance
  • Overdominance
  • No dominance
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8
Q

How is genetic information transferred?

A

DNA

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9
Q

_______________ pieces of DNA carry the same genes.

A

Homologous

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10
Q

A(n) ____________ is an alternative form of a gene.

A

allele

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11
Q

___________ genes ARE functionally the same, while ________________ genes ARE NOT functionally the same.

A

Homozygous ; heterozygous

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12
Q

True of False. A genome is most of the genes in a cell or organism.

A

False! A genome consists of ALL genes in a cell or organism.

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13
Q

A ___________ allele has an effect on the phenotype when it is homozygous AND heterozygous.

A

dominant

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14
Q

A ____________ allele has an effect on phenotype ONLY when it is homozygous.

A

recessive

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15
Q

Additive effect is:

A

the combined effects of genetic alleles at two or more gene loci are equal to the sum of their individual effects.

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16
Q

For complete dominance, what two genotypes have the same phenotype?

AA
aa
Aa

A

AA and Aa

17
Q

True or False. Incomplete dominance has a heterozygous genotype (Aa) express a phenotype in between the homozygous genotypes (AA and aa), except it is NOT exactly midway.

A

True!

18
Q

No dominance has the heterozygous genotype’s (Aa) phenotype exactly in between the homozygous genotypes (AA and Aa) or partially toward one end?

A

Exactly in between

19
Q

What is the difference between No Dominance and Partial Dominance?

A

For heterozygous genotypes, No Dominance phenotypes lay exactly in between the homozygous genotypes.

Partial dominance lays toward one end or the other. NOT exactly in the middle.

20
Q

In Codominance, how many phenotypes will there be with a simple genotype

(example: AA, Aa, aa)

A

3

21
Q

In Overdominance, where does the heterozygous genotype’s expression land in comparison to the homozygous genotypes?

A

HIGHER than the average of both homozygous genotypes.

22
Q

Define gene interaction:

A

The interactions between two or more genes result in a phenotype that differs from the phenotype expected if the genes were independent of each other.

23
Q

Define epistasis in your own words.

A

When the expression of one gene affects the expression of another on another loci.

24
Q

What does G, in P = G + E, expand into? And what do each letter stand for?

A

G = D + I

D = dominance

I = epistasis

25
Q

What are two types of gene-trait relationships that we mentioned in class?

A

Pleiotropy and Lethal Genotypes

26
Q

What is the difference between epistasis and pleiotropy?

A

Epistasis is one gene expression affecting another gene expression (of the same trait).

Pleiotropy is one single gene affecting multiple traits.

27
Q

Define genomic imprinting.

A

The ability of a gene to be expressed depends on the sex of the parent that the gene is coming from.

28
Q

What are the three kinds of sex-related inheritance?

What is an example of each?

A

Sex-linked - Color blindness in males only
Sex-limited - milk and egg production in females only
Sex-influenced - Scurs are more frequent in males

29
Q

What is an example of a non-additive effect?

A

Any form of dominance.