Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Stem Cells and Regeneration > Cloning (Lecture 5) > Flashcards

Cloning (Lecture 5) Flashcards

1
Q

Cloning definition

A

making duplicates of genetic material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cloning in nature

A
  • gardening
  • lower animals (asexual reproduction)
  • monozygotic twins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Preformationism vs. Epigenesis

A
  • preformationism –> 1600s; came from the church; shape of embryo exists before conception from god’s vision
  • epigenesis –> the shape of the embryo unfolds through development (originally from Aristotle)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Timeline to cloning

A

look at website with timeline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Roux-Weissman hypothesis

A
  • 1800s
  • Weissman states that genetic material diminishes with each cell division
  • natural examples of regeneration made this hypothesis questionable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hans Driesh

A
  • 1894
  • replicated sea urchins
  • concluded that genetic material is not lost with cell division in vertebrates (nuclear equivalence)
  • Hans Spemann replicated this in salamanders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

First nuclear transplants

A
  • 1939 Amoeba (comandom and defonbrune)
  • 1952 first true vertebrate nuclear transplantation; rana pipens (briggs and king)
  • 1958-1962 xenopus laevis (gurdon)
  • 1962 axolotl salamander
  • 1996 dolly the sheep
  • 2018 hua hua and zhong zhong the monkeys
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Hans Spemann early example of nuclear transfer experiment 1928

A
  • split the one embryo into two using a piece of hair as a noose
  • side with nucleus continues to divide and then undo noose and nucleus moves to other side to develop that side
  • leads to two salamanders being generated
  • two possibilities:
  • – all cells are equal at this stage
  • – cytoplasm can make the cell in effect “start over”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

a fantastical experiment 1938

A

question: can the embryonic environment signal to somatic cell to generate animal?
test: transplant nucleus from somatic cell (non-reproductive) into egg
result: died in 1941 and then WWII so science slowed during this era

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Briggs and King 1952

A
  • blast an oocyte nucleus with radiation so it can’t divide or pluck it out
  • listen to recording for rest
  • concluded that somatic cells can be reverted back to a pluripotent state (aka known as SCNT)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

human IVF led to …

A

methodology for mammalian cloning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Three varieties of cloning

A
  • reproductive cloning (generate offspring)
  • therapeutic cloning (generate stem cells for transplantation into patient)
  • research cloning (in vitro modeling of diseases using patient defects and genetic background)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Research cloning

A
  • most diseases arise from several possible genetic defects; one cell line for all will not work for modeling disease
  • SCNT can be used for research cloning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Therapeutic cloning

A
  • if the diseases allele can be corrected then the “normal” cell can be transplanted into diseased patient
  • SCNT can be used for therapeutic cloning
  • e.g. correcting genetic defect and then transplanting it back
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Reproductive cloning - first cloned mammals

A
  • 1984 steen willadsen performed nuclear transfer from embryos to generate cloned sheep
  • 1987 neal first generated first cloned cows from embryos named fusion and copy (made clone of exact organism)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Process of cloning sheep

A
  • donor nucleus taken from sheep’s udder
  • egg cell taken from adult female sheep
  • nucleus of egg cell is removed
  • donor nucleus and egg cell are fused using electric shock
  • fused cell divides normally
  • embryo placed in uterus of a foster mother
  • embryo develops normally into a lamb (dolly)
17
Q

Reproductive cloning - dolly and bonnie 1997

A
  • took so long to go from cloning frog to cloning sheep is because of size difference and other factors
  • not efficient at all because so many blastocysts made were not good enough to implant, and most implanted did not develop into viable lamb (most that did develop had abnormalities)
  • found that bone marrow cell was better than skin cell for outcomes
18
Q

Comparing SCNT (NT-ESC) to iPSC

A
  • pros for iPSC
  • – doesn’t require egg donors
  • pros for SCNT
  • – have more complete reprogramming because using pluripotent environment (using egg extract instead of transcription factors)
  • – can be used for mitochondrial therapy (able to replace mitochondria of donor with healthy host)
19
Q

Human cloning fraud

A
  • Hwang Woo-suk said they cloned human embryos but they didn’t
  • manipulated their images
  • damaged public’s outlook on stem cell research
  • increased attention to research ethics of stem cell research (showed stem cell community can police itself for fraudulent activity)
20
Q

Can ESCs or iPSCs generated from human cells turn into mature, functional tissues and organs?

A
  • works in chimera mice, but not primates at blastocyst stage
  • primate chimeras are possible when morula stage is used
  • cloning by current methods would likely not work in humans
21
Q

Human therapeutic cloning

A
  • problem –> location of human nucleus is tough to remove

- if don’t remove host nucleus in human fibroblast, can generate blastocyst; never will be viable because triploid

22
Q

Human ESCs derived by SCNT

A
  • what hwang lied about but real deal by Mitalipov
  • took so long because needed to stop development of oocyte at particular stage of mitosis
  • added caffeine to change intercellular pathway
  • all hallmarks of pluripotency
23
Q

Monkeys cloned with dolly the sheep technique

A
  • good for disease studies
  • increased efficiency in primates by adding mrna to block deacetylace and opens up chromatin
  • nothing stopping human cloning other than ethics
24
Q

Mitochondrial replacement therapy

A
  • three parent baby technique
  • seems to have cured mitochondrial defect
  • unfertilized donor egg with normal mitochondria and remove spindle and associated chromosomes from donated egg
  • remove spindle and associated chromosomes from mother’s egg (abnormal mitochondria) and transfer into empty donor egg
  • reconstituted egg is fertilized with sperm from father
  • embryo with normal mitochondria and maternal and paternal genome transferred to the uterus

Stem Cells and Regeneration (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions