L11 Flashcards

1
Q

What is EPISTASIS?

A

interaction between 2 or more gene that controls ONE PHENOTYPE

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2
Q

What are the RATIO for recessive epistasis ususally?

A

9:4:3

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3
Q

Why is the ALBINO gene EPISTATIC to all other coat colours??

A
  • Mutation in albino gene
  • No tyrosiNASE produced
  • TyronsinASE enzyme is responsible for converting tyrosin into precursor for melanin
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4
Q

What is the typical ratio of DOMINANT epistasis?

A

12;3:1

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5
Q

Remember the parental genotype of 9:7 ratio of puprple and white flowers

A

parents = PP ww x pp WW
ww recessive is epistatic to dominat, when ww, regardless of wethere the purple alle is present it will not be expressed

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6
Q

What are the two type of epigenetic tags and how do they affect genes?

A

DNA methylation
Histone modification
They can alter the chromatin structure within DNA, which will alter gene expression

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7
Q

What is MATERNAL imprinting?

A
  • maternal allele is IMPRINTED hence silenced
    therefore embryo will express paternal alleles
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8
Q

What is paternal imprinting?

A
  • paternal allele is imprinted and silenced
    maternal alleles are expressed in embryo
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9
Q

What type of imprinting does the IgF2 have and can you explain how it affects organism?

A

IgF2, is maternally imprinted, therefore maternal alleles are not expressed in the offspring even if functional
If father gene fort IgF2 is mutant it will have dwarfism effect on the offspring

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10
Q

What is the Prader-willi syndrome?

A
  • paternal origin deleted
    Due to the lack of maternally imprinted genes (polygenic)
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11
Q

What is Angelman syndrome?

A
  • maternal origin is deleted due to lack of paternally imprinted genes
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12
Q

What is the genetic conflict hypothesis in relation to genomic imprinting?

A
  • Paternal gene = promotes growth
  • Maternal gene = suppresses growth
  • Paternal related to promote growth as it may have multiple partners so wishes to promote growth of all of his offspring
  • maternal supresses as it would prefer it to sort of equally distribute fitness
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