3.C.2 Variation
Take your own notes for this section on the
back of your 3C1 notes.
Turn in when you have complete both.
Biological systems have multiple
processes that increase genetic
variation.
Sources of Genetic Variation
Prokaryotes
•
•
•
•
Random mutation
Conjugation
Transformation
Transduction
Eukaryotes
•
•
•
•
Random mutation
Crossing over
Random assortment
Random fertilization
Ways of obtaining of genetic variation
in prokaryotes:
Random mutation: the imperfect nature of
DNA replication and repair increases
variation.
Prokaryotes, which reproduce through
binary fission, can obtain genetic variation
through the horizontal transfer of genetic
information.
Bacterial conjugation is the transfer of
genetic material, usually a plasmid,
between bacterial cells by direct cell-to-cell
contact or by a connection between two
cells called a pilus.
In transformation, exogenous genetic
material from the surroundings is
incorporated into a bacterial cell and
expressed, resulting in genetic alteration
of the cell.
In transduction, DNA is transferred
from one bacterium to another by
a virus called a bacteriophage.
viral vector
Eukaryotes reproduce by sexual
reproduction, increase genetic variation by:
Random Mutation
Random Fertilization
•
•
•
•
Random mutation
Crossing over
Random assortment
Random fertilization
Crossing Over
Random Assortment
Reproductive processes that increase
genetic variation are evolutionarily
conserved and are shared by various
organisms.
Learning Objectives:
LO 3.27 The student is able to compare and
contrast processes by which genetic variation is
produced and maintained in organisms from
multiple domains.
[See SP 7.2]
LO 3.28 The student is able to construct an
explanation of the multiple processes that increase
variation within a population. [See SP 6.2]