Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7 th edition
Chapter 9 : Molecular structure of DNA and RNA
1
, Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7 th edition
9.1: Identification of DNA as the genetic material
- Genetic material must meet four criteria to fulfil its role
o Information: it must contain the information necessary to construct an organism, it
determines the inherited traits
o Transmission: reproduction: the material must be passed (parents to child)
o Replication: it must be copied to be passed
o Variation: genetic material must vary in ways that can account for the known phenotypic
differences within each species.
- Weismann and Nageli: chromosomes carry the genetic material. They contain DNA and proteins,
RNA is found in the vicinity. Further research:
Griffith’s experiments indicated that genetic material can transform streptococcus
- Griffith studied the bacterium Streptococus pneumoniae (pneumococci). Certain strains secrete a
polysaccharide capsule, some don’t. Streaked onto petri scales with a solid growth medium
the capsule-secreting strains produce colonies with a smooth morphology, the strains without
produce rough colonies.
- These different forms also vary in their virulence or ability to cause disease
o Type S capsule allows bacteria to escape attack by immune system
o Type R destroyed by the animal’s immune system
o Type S heat killed mouse survived
o Type R + Type S heat killed mouse died, living type S was found
- Type R was transformed into type S by the dead type S transformation
o The transformed bacteria had the information to make a capsule, variation for the ability
to create a capsule, the genetic material necessary to create a capsule must be
replicated to be transmitted from mother to daughter cell (cell division).
o Conclusion: genetic material from the dead type S had been transferred to the living type
R and provided it with a new trait.
2
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7 th edition
Chapter 9 : Molecular structure of DNA and RNA
1
, Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7 th edition
9.1: Identification of DNA as the genetic material
- Genetic material must meet four criteria to fulfil its role
o Information: it must contain the information necessary to construct an organism, it
determines the inherited traits
o Transmission: reproduction: the material must be passed (parents to child)
o Replication: it must be copied to be passed
o Variation: genetic material must vary in ways that can account for the known phenotypic
differences within each species.
- Weismann and Nageli: chromosomes carry the genetic material. They contain DNA and proteins,
RNA is found in the vicinity. Further research:
Griffith’s experiments indicated that genetic material can transform streptococcus
- Griffith studied the bacterium Streptococus pneumoniae (pneumococci). Certain strains secrete a
polysaccharide capsule, some don’t. Streaked onto petri scales with a solid growth medium
the capsule-secreting strains produce colonies with a smooth morphology, the strains without
produce rough colonies.
- These different forms also vary in their virulence or ability to cause disease
o Type S capsule allows bacteria to escape attack by immune system
o Type R destroyed by the animal’s immune system
o Type S heat killed mouse survived
o Type R + Type S heat killed mouse died, living type S was found
- Type R was transformed into type S by the dead type S transformation
o The transformed bacteria had the information to make a capsule, variation for the ability
to create a capsule, the genetic material necessary to create a capsule must be
replicated to be transmitted from mother to daughter cell (cell division).
o Conclusion: genetic material from the dead type S had been transferred to the living type
R and provided it with a new trait.
2
