| list three potential issues regarding cloning | → susceptibility to disease – crops and animals with no genetic variation are more susceptible to environmental changes and disease, leaving the human population vulnerable to wide scale food loss if all our food is clones
→ high failure rate – somatic cell nuclear transfer has a very low success rate (0.1-3%)
→ adverse health effects – many cloned animals have displayed impaired immune systems and organ malformations
→ premature aging – due to the shortening of the telomere cloned animals tend to have lower life expectancies
→ many people are worried about the fact that cloned food products should be labelled clearly despite the FDA announcing that meat from cloned animals is identical to normal meat |
| what are the four types of cloning | cuttings/grafts, tissue culture, embryo splitting, and nuclear transfer |
| what are cuttings and grafts used for | regularly used in agriculture and help retain favourable genetics - forms of asexual propagation |
| define asexual propagation | asexual propagation involves taking a part of one parent plant and causing it to regenerate itself into a new plant. The resulting new plant is genetically identical its parent. |
| what are cuttings | oldest form of cloning, and it is a process where a part of an existing plant (stem, root, or lead) that if replanted or placed in water where they can regrow into clones of their parent plant |
| what is the process of grafting | grafting is slightly more difficult then cuttings, and it is a process where one plant is transferred to another with a well-developed root system (rootstock – root portion of grafted plant) – the rootstock is chosen as it has desirable characteristics the cultivar (the desired variety of plant) doesn’t have |
| what is rootstock | used in grafting plants - root portion of grafted plant |
| what are cultivars | used in grafting and they are the desired variety of plant |
| list four advantages of using grafts or cuttings | - increased yield
- increased tolerance to extreme weather
- increased efficiency, disease resistance
- early fruiting
- new plant types can be produced |
| what is micropropagation | technique to grow large numbers of plants rapidly
- plant tissue, or single cells is placed in a culture medium to grow quickly |
| list two uses of micropropagation | it is used in agriculture to grow large crops with idea characteristics but is also going to be used to recover endangered plant species |
| list 2 disadvantages of using micropropagation | very expensive and lack of genetic identity |
| list three advantages of using tissue culture | it is very efficient, new genes can be introduced, and easy to control growth condition |
| what is embryo splitting | in this technique a blastocyte is split-up and each new blastocyte is implanted into a surrogate mother – each new embryo is identical and will create identical offspring
-> before an embryo undergoes gastrulation all the cells are pluripotent, and an individual cell can grow into a whole organism |
| what is nuclear transfer | nucleus is removed from an fertilised egg and replace it with another nucleus (usually from a somatic cell – somatic cell nuclear transfer) – the egg is then retransplanted back into the host or surrogate mother |
| what is somatic cell nucleus transfer | nucleus is removed from unfertilised eggs and replaced with a nucleus from a somatic cell
-> egg is then transplanted back in to host |
| who was dolly the sheep | in 1996 dolly the sheep was born, and she was the first animal to be successfully born via nuclear transfer however she had a very low life span (half of usual due to decreased telomere length) |
| what are some disadvantages of nuclear transfer | - low success rate (0.1-3%)
- offspring have lower life spans
- adverse health effects |
| why do organisms who went through nuclear transfer tend to have lower life spans | telomeres are at the end of chromosomes and shorten as you age – when chromosomes in somatic cells are transferred in to a new nucleus the telomere length is shorter than usual leading to a shorter life span as a newborn clone is already genetically old |
| what are monozygotic twins | they are identical twins that have identical genes
- natural examples of genetically identical individuals |
| define reproductive cloning | defined at the deliberate production of genetically identical individual |
| list the two techniques used in reproductive cloning | embryo splitting and nuclear transfer |
| what is one possible use of reproductive cloning (not in agriculture) | Could potentially help infertile people have children who are genetically related (identical) to them |
| what is therapeutic cloning | Involves creating a cloned embryo for the sole purpose of collecting embryonic stem cells |
| what processes are used in therapeutic cloning | nuclear transfer - usually somatic cell nuclear transfer |
| what is a possible advantage of therapeutic cloning | through somatic cell nuclear transfer, a person can create their own embryonic stem cells which they can use to treat diseases they may have without the issue of immune rejection |
