Evo-devo 2 Flashcards

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1
Q

Dog Evolution factors:

A
  • reproductive separation and limited effective population sizes of established breeds provide extensive opportunity for divergence - genetic drift
  • breeds are also under selection for a variety or morphological and behavioural traits - adaptive
  • cranial variation with functional consequences, such as breathing
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2
Q

Modularity

A
  • identified as independence amoung groups of phenotypic traits
  • can help organisms avoid trade-offs and likely alters the rate and direction of evolution-modularity may predispose dogs for rapid evolution of jaw length
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3
Q

BMP

A

Bone morphogenetic protein

-have known role in craniofacial development

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4
Q

Morpholinos

A

molecules we can design to block the activity of specific genes

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5
Q

Zebrafish (danio rerio)

A
  • model organism for genetic manipulation
  • Injection of BMP3 morpholino at the one-cell stage
  • Knocks down the function of BMP3 throughout development
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6
Q

Loss or reduction of BMP3 function causes..

A
  • shorter flatter face
  • BMP3 is the reason why pugs, bulldogs, are brachycephalic
  • also shows that the effect of BMP3 in a fish is similar to that in a dog - conserved toolkit gene
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7
Q

Summary

A
  • Divergence among dog breeds appears to be due to standing variation from their common grey wolf ancestors
  • The main change in dog skulls involves lengthening and shortening of the jaws
  • Modules in the skull may contribute to the evolution of these changes in jaw length by circumventing tradeoffs
  • Jaw length in dogs seems fairly simple, being largely explained by five regions of the genome
  • BMP3 looks to be especially important for determining jaw length (alleles are fixed between dolichocephalic and brachycephalic breeds, and it effects zebrafish jaw length)
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