4: Reed et al 2007

Question 1

how many years of coevolution have primate sucking lice experienced with hosts?

Answer 1

25 million years

Question 2

how many mya did chimpanzees and human lice share a common ancestor?

Answer 2

6mya

Question 3

what do phylogenetic analyses suggest about Pediculus and Pthrius?

Answer 3

monophyletic sister taxa

Question 4

when did pthrius share a common ancestor and how does this relate to the divergence of human and gorillas?

Answer 4

shared ancestor 3-4mya

divergence 7mya

Question 5

what do divergence data estimates suggest about the coevolutionary history of anthropoid primates and lice?

Answer 5

includes cospeciation, parasite duplication, extinction, host switching

Question 6

what are sucking lice?

Answer 6

obligate ectoparasites of eutherian mammals

Question 7

what are humans parasitised by?

Answer 7

2 genera

• pthrius shared with gorillas
• pediculus shared with gorillas

Question 8

what is the recent host switch hypothesis? (3)

Answer 8

• predict perfect cospeciation between primates and lice
• gorilla and human pediculus occured at the same time as split between hosts 6mya
• single host switch where pthrius lice moved from gorilla to human

Question 9

what is the pair of lice lost hypothesis? (6)

Answer 9

• duplication event creating lineages leading to pediculus and pthrius
• pthrius lice divergence corresponds to host divergence
• humans retained both genera
• chimps lost pthrius
• gorillas lost pediculus
• sorting event

Question 10

what is the likely reason ? (7)

Answer 10

• 3-4mya pthrius species switched from gorilla lineage to humans (host switch)
• pediculus species diverged with host 6mya
• gorillas retained pthrius and humans retained pediculus
• 13mya pthrius and pediculus diverged by duplication event
• each genus could cospeciate with descendent hosts
• one duplication, 2 losses, 1 host switch
• combination of the 2 hypotheses