Download Horizontal Transfer

Warm-Up (1/22)
On the piece of white paper from the back, answer
the following question.
Illustrate (via model,
diagram, cartoon, et cetera)
how viral replication
introduces genetic variation
in the viral population.
Name
Date
Period
3C.1c: Errors in mitosis or meiosis can result in changes in phenotype.
3C.1c.1: Changes in chromosome number often result in new
phenotypes, including sterility caused by triploidy and increased vigor of
other polyploids.
3C.1c.2: Changes in chromosome number often result in human
disorders with developmental limitations, including Trisomy 21 (Down
syndrome) and XO (Turner syndrome).
3C.2b: The horizontal acquisitions of genetic information primarily in
prokaryotes via transformation (uptake of naked DNA), transduction (viral
transmission of genetic information), conjugation (cell-to-cell transfer), and
transposition (movement of DNA segments within and between DNA
molecules) increase variation.
3C.3a: Viral replication differs from other reproductive strategies and
generates genetic variation via various mechanisms.
3C.3a.1: Viruses have highly efficient replicative capacities that allow for
rapid evolution and acquisition of new phenotypes.
3C.3a.5: Related viruses can combine/recombine information if they
infect the same host cell.
3C.3b: The reproductive cycles of viruses facilitate transfer of genetic
information.
3C.3b.1: Viruses transmit DNA or RNA when they infect a host cell.
3C.3b.2: Some viruses are able to integrate into the host DNA and
establish a latent (lysogenic) infection.
Chromosomal “Mutations” in Eukaryotes
Triploidy (3n) often results
in sterility.
“nondisjunction”
1m
1p
1p
1m
2p
2p
2m
3p
3m
4m
4p
3p
4p
0 copies of
chr. 4
1m
2p
3p
4m
4p
3m
4m
2 copies of
chr. 4
uneven segregation
2m
fertilization
3 copies of
chr. 4
Chromosomal “Mutations” in Eukaryotes
“Trisomy 21” results in
Down’s Syndrome
A normal karyotype
Down’s syndrome karyotype
Chromosomal “Mutations” in Eukaryotes
Monoploidy (1n) of the sex
chromosomes results in
XO: Turner’s Syndrome
A normal karyotype
Turner’s Syndrome karyotype
Chromosomal “Mutations” in Eukaryotes
Genetically-modified
polyploidy produces
bigger, more productive
crops.
Diploid (2n)
banana
Tetraploid (4n)
banana
Horizontal Transfer in Eukaryotes
Transposition of pieces
of DNA occurs in
eukaryotes
some
chromosome
some other
chromosome
“transposon”
Horizontal Transfer in Eukaryotes
Transposition of pieces
of DNA occurs in
eukaryotes
Barbara McClintock
Nobel Prize, 1983
~1940’s
Discovered a pigment
transposon in maize
Horizontal Transfer in Prokaryotes
Plants and
animals have sex,
but bacteria can’t.
So how do they
increase
genetic
variation?
Horizontal Transfer in Prokaryotes
Transformation is
uptake of freefloating DNA by
bacteria.
Added arabinose –
GFP genes activated
Horizontal Transfer in Prokaryotes
Conjugation =
bacterial “sex”
Horizontal Transfer in Prokaryotes
Transduction =
injection of
viral DNA
Horizontal Transfer
What’s the difference
between horizontal
and vertical transfer?
Critical Thinking Question #1
Compare and contrast the processes by which
genetic variation is produced and maintained in
prokaryotes versus eukaryotes.
3C.1c: Errors in mitosis or meiosis can result in changes in phenotype.
3C.1c.1: Changes in chromosome number often result in new
phenotypes, including sterility caused by triploidy and increased vigor of
other polyploids.
3C.1c.2: Changes in chromosome number often result in human
disorders with developmental limitations, including Trisomy 21 (Down
syndrome) and XO (Turner syndrome).
3C.2b: The horizontal acquisitions of genetic information primarily in
prokaryotes via transformation (uptake of naked DNA), transduction (viral
transmission of genetic information), conjugation (cell-to-cell transfer), and
transposition (movement of DNA segments within and between DNA
molecules) increase variation.
3C.3a: Viral replication differs from other reproductive strategies and
generates genetic variation via various mechanisms.
3C.3a.1: Viruses have highly efficient replicative capacities that allow for
rapid evolution and acquisition of new phenotypes.
3C.3a.5: Related viruses can combine/recombine information if they
infect the same host cell.
3C.3b: The reproductive cycles of viruses facilitate transfer of genetic
information.
3C.3b.1: Viruses transmit DNA or RNA when they infect a host cell.
3C.3b.2: Some viruses are able to integrate into the host DNA and
establish a latent (lysogenic) infection.
Transduction Produces Variation
Lysogenic viruses transfer
bacterial genes to other
bacteria.
The Lytic Cycle
Viral replication happens
very quickly.
∴, many generations
turn over quickly.
∴, viruses accumulate
mutations and new
phenotypes very
quickly.
PLUS, retroviruses
cannot errorcheck their RNA.
Lysis
Critical Thinking Question #2
Explain how a virus can transfer a
bacterial gene from one host to
another host.
Closure
On the piece of white paper from the
back, answer the following question:
Explain, referring to both
prokaryotes and eukaryotes,
how genetic variation in an
organism results in phenotypic
variation in populations.
Name
Date
Period
Scale
1 – 10