Sources Of Variation Flashcards

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1
Q

Variation

A
  • existing genetic variation in an individual can be rearrange into different combinations by random assortment and crossing over (recombination) during meiosis when gametes are formed.
  • Further variation arises due to the random fertilisation of gametes during sexual reproduction
  • The environment can also affect the expression of genes and resulting phenotype
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2
Q

Mutations

A
  • New genetic variation arises from changes in the DNA of a cell called mutations.
  • They can be beneficial, harmful or neutral.
    &
  • Mutations can occur spontaneously or induced
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3
Q

DNA

A
  • DNA is a double-stranded molecule made up of a sequence of pairs of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). This code is read in sets of three pairs called codons which code for specific amino acids.
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4
Q

Point/substitution

A

One base pair is swapped for another

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5
Q

Silent

A

The change occurs in non-coding regions of DNA so it doesn’t affect the phenotype

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6
Q

Missense

A

The codon now codes for a different amino acid

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7
Q

Nonsense

A

The change codes for a stop codon, resulting in an incomplete protein

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8
Q

Insertion

A

Extra base pairs are inserted into the DNA sequence

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9
Q

Deletion

A

Base pairs are lost from the DNA

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10
Q

Duplication

A

A section of the DNA is repeated

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11
Q

Translocation

A

Sections of DNA either swap places or chromosomes join together

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