Lecture 15: Mechanisms of Microbial Evolution

Question 1

homologous

Answer 1

related sequence that implies common ancestry

Question 2

gene famlies

Answer 2

groups of gene homologs

Question 3

paralogs

Answer 3

genes in an organism that is the result of gene duplication

Question 4

orthologs

Answer 4

similar genes that differ because of speciation

Question 5

evolution

Answer 5

change in allele frequencies in a population over time

Question 6

mutations

Answer 6

random changes in DNA sequences

Question 7

recombination

Answer 7

breaks & rejoins DNA segments to make new genetic combinations

Question 8

nonhomologous / homologous

Answer 8

non- does not require similarity
homologous- requires similarity

Question 9

fitness

Answer 9

ability of an organism to produce progeny & contribute to genetic material for future generations

Question 10

deleterious mutations

Answer 10

increase fitness & removed by natural selection

Question 11

beneficial mutations

Answer 11

increase fitness & are favoured by natural selection

Question 12

a marker that colours cells red or white enables…

Answer 12

fitness measurement of evolved strains

Question 13

horizontal gene transfer

Answer 13

transfer of genetic information between cells

Question 14

what 3 mechanisms are used to transfer genes in prokaryotes?

Answer 14

1. transformation
2. transduction
3. conjugation

Question 15

where are metabolites found?

Answer 15

host cytoplasm

Question 16

T or F: deletions removing biosynthetic genes might only have little effect on fitness

Answer 16

True

Question 17

3 characteristics of horizontal gene transfer that differs from recombination

Answer 17

1. unidirectional
2. asymmetrical
3. not constrained

Question 18

gene conversion

Answer 18

replacement of recipient copy with donor copy

Question 19

if there is no fitness benefit what happens to gene transfered from horizontal gene transfer

Answer 19

it is deleted over time

Question 20

the mobilome

Answer 20

consists of all mobile genetic elements in a genome

Question 21

insertion sequences

Answer 21

can generate chromosomal re-arrangements

Question 22

how to detect horizontal gene flow

Answer 22

presence of DNA with GC content or codon bias that differs slightly

Question 23

what do horizontally transferred genes do not encode

Answer 23

core metabolic functions

Question 24

comparative genomics

Answer 24

uses whole genome sequencing technologies to analyze gene content

Question 25

pan/core genome concept

Answer 25

genomes consist of 2 species

Question 26

core genome

Answer 26

shared by all strains of the species

Question 27

pan genome

Answer 27

includes all the optional extras present in some but not all strains of species

Question 28

how are chromosomal islands acquired?

Answer 28

through horizontal gene transfer

Question 29

chromosomal islands often belong to the ( ) genome

Answer 29

pan