Asexual Reproduction/cloning Exam 3

Front 1

asexual reproduction definition

Back 1

without sex, produces offspring that are genetically identical to the single parent organism

Front 2

plant cloning vs. farm animal cloning

Back 2

plant cloning has been around for thousands of years where as farm animal cloning has been around for only just over ten years

Front 3

cloning definition

Back 3

a procedure that generates individuals with identical nuclear genomes

Front 4

nuclear transfer (NT)

Back 4

the transplantation of a nucleus derived from one cell into a second enucleated cell, usually an oocyte

Front 5

nuclear reprogramming

Back 5

the epigenetic re-instruction of the nucleus to undertake an alternative genetic program, usually a program in embryogenesis

Front 6

therapeutic cloning

Back 6

nuclear transplantation to produce stem cells

derivation of stem cells from the product of nuclear transfer

Front 7

jonh gordon

Back 7

cloned frogs in 1960s

used somatic cells harvested from the intestines

in one case, cells harvested from a tailbud stage tadpole which was carrying albino gene

nucleus was transferred to wild type frog

resulting in albino offspring

Front 8

affect of nucleus age on success rates of nuclear transfer

Back 8

as the age of the nucleus increase, the success of nuclear transfusion decrease

Front 9

two types of epigenetic changes that occur in DNA

Back 9

1. methylation: DNA chemically altered by adding methyl groups in place of hydrogens in particular sites within the sequence of a gene. this represses gene activity

2. alteration in the histone proteins, that changes the way the chromatin is packaged. this alters the activity of the gene.

both are reversible

Front 10

steps of reproductive cloning process

Back 10

1. stem cell harvested from donor

2. stem cells cultured

3. nucleus of recipient cell removed then added to cultured donor cells

4. fusion of the recipient cell and donor cell occurs

5. implantation occurs after the blastocyst stage is reached, into a surragote uterus

Front 11

potential donors for nuclear transfusion

Back 11

blastocyst

early embryo

fetus

adult

Front 12

mammalian cloning

Back 12

sheep were successfully cloned in 1997

ian wilmut used cells from the mammary gland

made sure that the donor cells were in the GO or resting phase of the cell cycle (not yet differentiated)

Front 13

why did dolly die?

Back 13

telemere length too short

Front 14

factors that affect nuclear transfusion

Back 14

stage of the cell cycle the donor nucleus is at

needs to be in the GO, quiscent phase

once the cell enters the cell cycle and the nucleus begins to actively duplicate its DNA in preparation for cell division, the success rate becomes much lower

Front 15

roscovitiline

Back 15

lower percentage of blastocysts formed, but the blastocysts that form are healthier and have a higher number of cells

increases the success rate of cloning

helps maintain cells in GO phase

Front 16

nuclear transfer efficiency in bovine

Back 16

nucleus transfer = <50%

IVF = 90%

natural = 95%

Front 17

characteristics of a NT pregnancy

Back 17

heavier fetal membrane with fewer placentomes

underdeveloped chorionic and endometrial epithelium

abnormal placenta -- high mortality

imcomplete nuclear reprogramming

Front 18

characteristics of Large offspring syndrome (los)

Back 18

heavier fetal membrane

fewer placentomes

cardiovascular disorders

extremely large offspring

peri-natal death common

Front 19

cotyledon development in los

Back 19

major problem with development

leads to overcompensation of growth in the second half of pregnancy

Front 20

what is a hydrop?

Back 20

presence of acute accumulation of fluid in the allantois

also characterized by enlarged placentomes, oversized fetuses

causes severe animal welfare issue for the recipient

Front 21

what is the frequency of hydrops?

Back 21

range from 0-40% in clones

<0.5% in normal pregnancies

Front 22

Methylation

Back 22

replacement of a hydrogen atom with a methyl group

catalyzed by enzymes

Front 23

epigenetics

Back 23

reversible changes in gene function without a change in DNA sequence

Front 24

imprinting

Back 24

occurs when a gene is expressed according to their parent of origin

resulting in a differential expression of the two parental alleles in somatic cells

Front 25

what is thought to be the key cause for placental abnormalities in nuclear transfer?

Back 25

loss of epigenetic asymmetry

Front 26

benefits of cloning

Back 26

produce cloned animals that produce human proteins that have therapeutic uses in treatment of disease

use stem cells from humans to culture a multitude of different cells to use in a therapeutic way to cure diseases, such as diabetes