26 - Phylogenetics - Using Trees

Question 1

What is a gene tree?

Answer 1

• within phylogenetic trees
• shows the spread of different alleles

Question 2

What are the possible outcomes of hybridisation?

Answer 2

• nothing - offspring infertile or unfit
• forms hybrid zones - specific areas of hybridisation
• exchanges a few genes - introgression
• form a new hybrid species

Question 3

What is allopolyploid speciation?

Answer 3

• hybridisation of two species
• keeps both copies of gametes
• increase in ploidy

Question 4

What is homoploid hybrid speciation?

Answer 4

• Where there is no genome duplication
• F1 hybrid has incompatibilities but is still fit enough
• BDMIs selected against in future generations
• only compatible combinations remain

Question 5

What is incomplete lineage sorting

Answer 5

• just because 2 species share the same allele, does not mean they are the closest related

Question 6

What is a monophyletic clade?

Answer 6

includes and most recent common ancestor and all of its dependents

Question 7

What is a polyphyletic clade?

Answer 7

does not include the common ancestors

Question 8

What is a paraphyletic clade?

Answer 8

Most recent common ancestor but not all of its decendents

Question 9

What is the effect of Neanderthal integression on toll-like receptors?

Answer 9

• increases their expression
• associated with an increase in allergies