Lesson 3: Microbial Phylogeny

Question 1

the field of study dedicated to
understanding the evolutionary
relationships between different groups of microorganisms, primarily bacteria, and archaea

Answer 1

Microbial Phylogeny

Question 2

Importance of microbial phylogeny

Answer 2

-development of antibiotics for infectious disease by identifying their vulnerabilities
-bioremediation strategies using microbes
-exploring earth’s diversity

Question 3

Challenges in Microbial Phylogeny

Answer 3

Similarites of microbes
Horizontal gene transfer

Question 4

TECHNIQUE
compares sequences of different microbes to infer
evolutionary relationships.

Answer 4

Comparative genomics

Question 5

TECHNIQUE

describe WGS

Answer 5

• comprehensive data of genomic sequences
  -provides data from AMR genes
  -time consuming and expensive

Question 6

______depict evolutionary
relationships between microbial groups over time using data from various techniques.

Answer 6

Phylogenetic tree

Question 7

Benefits of Studying Microbial Phylogeny

Answer 7

• improved objective classification instead of morphology-based

-functional prediction using mathematical models for exploring microbial function

-understanding interaction of microbes with their ecosystems

-interaction and relationship with other organism in the community

-sytematic study using methods beyond genomics

Question 8

How is microbial phylogeny being study

Answer 8

Polyphasic analysis: genotypic, phenotypic and phylognetic analyses

Question 9

Molecular phylogeny analysis

Answer 9

DNA sequences

Question 10

This classification involes, phenotypic, morphological (size, shape, structure), physiological, biochemical and genetic sequences

Answer 10

Polyphasic Analysis

Question 11

Why do we analyze DNA sequences to investigate microbial phylogeny

Answer 11

DNA sequences show history of evolution
mutations accumulate in DNA overtime
More mutations indicates longer evolutionary distance

Question 12

Obtaining DNA sequences

Answer 12

PCR- amplify genes
SSu rRNA- highly conserved, easy to sequence

Question 13

Genes inherited and are used for alignment

Answer 13

homologous genes

Question 14

adds gaps to
ensure positional homology

Answer 14

Sequence alignment

Question 15

Phylogenetic Tree elements

Answer 15

Rooted- ancestral position
Unrooted: relative but not most ancestral node
Branch lengths: number of evolutionary changes

Question 16

These values indicate confidence levels in the nodes

Answer 16

Bootstrap values

Question 17

Limitations in phylognetic tree

Answer 17

• Difficulty in choosing true tree (limited data)
• Homoplasy convergent evolution (similar traits or features
• horizontal gene transfer

Question 18

Origin of cellular life

Answer 18

building blocks of life (RNA, nucleotides, AA, lipds) form naturally on earth

Question 19

Location of life’s origin

Answer 19

Hydrothermal vent on ocean floor
stable conditions
energy sources (inorganic compounds)
Production of key molecules (AA, lipids, nucleotide bases, sugars)

Question 20

Possible first life form

Answer 20

RNA- first self-replication sysntem ( catalysis)

Question 21

Evolution of Life

Answer 21

RNA catalytic property was replaced with protein

DNA replaced RNA as the genetic material due to its stability

Question 22

What is LUCA

Answer 22

Last universal common ancestor 3.8-3.7 BYA