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5. Current reproductive technologies and genetic engineering have the
potential to alter the path of Evolution
Humans have always manipulated the gene pool and controlled breeding.
5.1 Identify - how the following current reproductive techniques may alter the genetic composition
of a population.
 Normally cattle produce one or two offspring per year. (sexual reproduction)
 From early times, artificial selection (animals selected for breeding was used to improve herd
quality e.g bulls which produced more meat, less fat, more milk, sheep with fine wool, high wool
yield.
 In the past a selected male was mated with many females
Artificial Insemination (AI) - Animals
1. Involves collecting semen from selected animals, then artificially introducing this into female - of the
same species.
2. This increases the number of offspring one animal could produce, (usually only one offspring/mating)
3. 1949 - semen could be frozen by controlling pH and adding chemicals
4. Now AI means that:
 many females can be fertilized
 females can be fertilised with sperm from far away places
 sperm can be stored and used after death of animal
5. In humans A.I is used - mothers egg and a donor sperm - legally the child is of the mother and the
husband at the time of birth
6. A.I changes the genetic composition of animals e.g a few selected genes become common in the herd,
other alleles are lost. Also can result in loss of genetic variation (could be serious if e.g disease
resistance is lost).
Artificial Pollination - Plants
1. Mendel used artificial pollination (pea plant experiment)
2. The process involves - remove stamens, collect pollen to be used, transfer donor pollen to stigma.
3. This process may alter the genetic composition - less variation
4. It is possible to create now species by this method eg. Wheat pollination with rye - produces an infertile
hybrid with desired traits - grows in cold climates, low nutrient soils. Chemicals can cause it to double
its chromosome number and so undergo is then fertile.
ACTION - Research – the following research is required. Follow the link to the web site that deals with the
Artificial insemination of goats.
http://www.goatworld.com/articles/ai/ai.shtml
Answer the following questions
1. List 3 advantages for using AI over natural breeding
2. Read point #6. Identify 2 important factors you would need to understand to successfully use AI
3. Read point #13 Identify 1 method to collect semen for AI of goats.
4. Write 2 statements on how you would store the semen.
5. Describe how the semen is used to AI the female goat or doe. (1 short paragraph)
CLONING
5.1 cont’d and 5.4 Process information from secondary sources to research a methodology used in
cloning organisms.
1. Cloning involves methods of asexual reproduction - the genetic information comes from one parent (the
two above still involve 2 sets of genes from two different parents)
2. Cloning of mammals has been done with sheep, mice, cattle.
3. The method used:
ACTION -Include your diagram of dolly here (See text book)
a) Obtain a somatic (body cell) of an adult animal and remove the nucleus - this is the donor nucleus.
b) Remove the nucleus from an unfertilised egg, of the same species.
c) Transfer the donor nucleus into the empty egg cell.
d) Culture the egg cell and donor nucleus until embryonic development begins.
e) Transfer the developing embryo into the uterus of a surrogate animal where it completes its
development.
ACTION – Research the life of Dolly and construct a flow chart to show the methodology used to clone
her.
ACTION – Discuss the life and times of SNUPPY at http://en.wikipedia.org/wiki/Snuppy at the bottom of
the page follow the link to cloned animals and identify other cloned animals.
Cloning of plants
Cloning plants - occurs both naturally and artificially eg suckers and runners are natural while cuttings and
tissue cultures are artificial.
Many plants naturally clone themselves by vegetative reproduction which leads to populations of identical
individuals.
ACTION -Tissue culture is a more complex cloning technique. Use your text book to outline the process of
TISSUE CULTURE
5.2 Outline the processes used to produce Transgenic “Species" and include examples of this
process and reasons for its use.
5.5 Include - analyse information from secondary sources to identify examples of the use of
transgenic species
1. Genetic make up is the genome - usually genes from one species cannot be transferred into another.
(Species will not mate and gametes from one species will not fertilise another.)
2. Genetic engineering technology allows genes to be transferred between two species. eg : human gene
into a bacteria, human gene into cows, bacterial gene into cotton plants.
3. An organism that has a "foreign" gene in its genome, is a transgenic organism. (A gene from a different
species.)
4. 1970 - discovery of enzymes that can cut DNA, producing recombinant DNA - has broken the species
barrier.
5. The method of transferring the gene can include: micro injecting the DNA, using a virus to carry the gene,
electric pulse to carry the gene and the gene gun.
6. Method:
 useful or desired gene is identified
 gene is "cut out" of its DNA using a cutting enzyme
 gene is inserted into the plasmid in bacteria.
 this is then called recombinant DNA
 the plasmid replicates in the bacteria therefore copies of the gene have been produced.
 these copies can then be introduced into fertilised cells or cells that will develop into new
transgenic individuals. These individuals will all have the new gene in their genome ie their
DNA and so are TRANSGENIC
ACTION – Design a flow chart to outline the methodology in using restriction enzymes to produce
transgenic species. Notes will be given in class and discussed. Look above at #6
ACTION – Use the web site
http://www.biotechnologyonline.gov.au/
1. Follow the yellow ball link to food and agriculture and research “A problem with Insects – The
Cotton Story” (Use the headings that are provided for you. Make a short summary)
Use these headings
a) What is cotton
b) Why do we grow cotton
c) What’s the problem with insects
d) A biotechnology solution to insect pests
2. Use the search engine Google and search for “spider web from goats milk” Discuss the impact
on society of transgenic species such as spider goats. Listen to the audio file at
http://www.uh.edu/engines/epi1717.htm
3. Research 1 other transgenic species of your choice (1 paragraph and image required)
4. Summarise your results in the table below.
Transgenic species
Bt Cotton
Transgene or organisms
involved
Benefits
Bacillus Thuringiensis
Produces natural pesticide that
kills caterpillars when they eat the
leaves so reduces costs and need
for spraying
Spider Goats
Your transgenic species
ACTION – Try this quick challenge http://agbiosafety.unl.edu/education/whowants.htm
SUMMARY
Example
Advantages
Artificial insemination and
pollination
1.
2.
3.
4.
5.
6.
7.
Cloning
1. many of the desired organisms
2. control the breeding program
3. increased yield, production
Transgenic species
1. improve productivity
2. increase resistance of plants
and animals to diseases,
pests and environmental
extremes
3. for medicines, vaccines
4. to study human diseases
5.5
increase yields
disease resistant
hybrid vigour
cheaper
more females
fertilised
sperm can be frozen
Disadvantages
Ethical Issues
1. inbreeding can cause recessive
traits to be expressed
2. reduced variation genes lost
1. reduced biodiversity
2. single parents
3. choose donor sperm
4. (legal problems)
1. limits variation
2. reduces genetic diversity
1. reduced biodiversity
2. people are concerned that it
could be applied to humans
3. need strict control over human
cell experiments
See below for ethical issues (this includes disadvantages)
Are we playing "God"?
Evidence to debate the ethical issues arising from the development and use of
transgenic species.
Ethical issues raise the question - " Should something be done just because it is possible?"
1. Concerns that genetic engineering of transgenic species has the capacity to disrupt the rate of gene
transfer between organisms and the way genes are transferred and so will disrupt evolutionary
relationships.
2. Transfer of genetic material is not occurring in an ecological context - genetic engineering could speed up
the rate of genetic change.
3. Concerns that genetically engineered organisms could be resistant to drugs.
4. Concerns about pollution of gene pools eg cross pollination from a genetically modified crop to a nonengineered crop.
5. Fears that accidents could result in the release of cancer cells, bacteria or viruses from GE laboratories.
6. Health risks associated with eating genetically modified foods - consumers object, labels must clearly
show what is in the food.
7. Concerns about the long term effects on the transgenic animal itself eg cows treated with GE growth
hormone develop mastitis.
8. Animal rights - the moral questions about creating transgenic animals eg transgenic pigs grow faster, are
leaner but can't stand because of arthritis, transgenic mice develop cancer.
9. Will we selectively breed humans - try to eliminate undesirable traits (eg Nazis in WWII).
ACTION – Add 3 new ethical issues to bring the total of points to 12
5.3 Discuss the potential impact of the use of reproduction technologies on genetic diversity
of species using a named plant and animal example that have been genetically altered.
2.5.3. Potential impact of reproduction technologies on genetic diversity.
The potential impact of transgenic species depends on how well the species competes. If the genes of the
transgenic species are an advantage in their environment - their gene pool will increase.
Genes from genetically engineering organisms have the potential to move from one gene pool to another.
Individuals vary within natural populations. This gives a species the ability to adjust to environmental
change. The use of reproduction technologies reduces this natural variation by deliberately producing large
numbers of identical organisms.
Genetic uniformity in crops results in more consistent growth rates and harvesting times which encourages
the trend towards monoculture in commercial agriculture. Widespread monoculture reduces the ability of
farmers to react to changes in the environment, such as new pests or rapid climate change. The Irish
potato famine is a famous example of how monoculture may create problems. Potatoes were originally
brought to Ireland form South America by the Spanish explorers and became the staple food of the
population within a fairly short time. The plants were grown vegetatively (natural cloning) and were all
genetically similar. When potato blight disease struck it wiped out the main food source and caused
widespread starvation.
The use of transgenic species impacts on genetic diversity. Initially, there is an increase in genetic
diversity; a gene from one species is placed into another species thus increasing the gene pool for that
species. But if large areas of land are planted with genetically identical crops this reduces genetic diversity
and leads to the loss of genes from a population. For example, some countries in Asia now use a small
number of genetically engineered varieties of rice instead of a wide selection of wild varieties adapted to
local conditions. Cloning animals also reduces the gene pool and may result in some genes being lost. It is
possible for transgenes to move from the original organism into the surrounding wild population through
natural reproduction processes. Our knowledge of the impact of these technologies is incomplete and
whole species or genes may be lost before we understand the value of them.
ACTION –
1. Define the following terms
a) Discuss
b) Reproductive technologies
c) Genetic diversity
2. Write a conclusion to support the above discussion by including a named plant and animal species.