Biotechnology in Crop Yields and Quality

If we are to use technology to improve our food supply on the island, we will need to investigate agricultural biotechnology. This includes new ways to improve crops and animals.

The information that makes an organism look and do what it is meant to, is stored as genes in the cells. The genes come from the mother and father: half from one parent and half from the other. The genes make up the genetic information and are stored on long strands called DNA. Each gene codes for a specific protein and these act either as building blocks or are action-molecules that join or separate other components of the cell. Our genes give us certain 'traits' (pronounced "trays" and not "trates"), which are visible characteristics such as large hands, small build or brown eyes.

Breeders have selected specific traits for plants and animals to give good food production. They chose a trait they like (e.g. strong stems, sweet fruit or lean meat) and then breed it into their crop or herd.

Genes also move in nature. Viruses transfer genes to the plants and animals they infect. As they move to new hosts, the viruses can take along some of the genes from the old host. This is just one way in which genes move between species in nature. We can also get changes to our genes when our cells divide. As the DNA copies move apart into each new cell, crossovers can occur between the DNA strands, causing new genes.

When scientists discovered that DNA has basically the same structure between all living organisms they realised that it would be possible to move genes, in the laboratory, between organisms. This led to a new technology called genetic engineering, or genetic improvement.

Island farmers seek solutions to insect damage and pesticide use.

Maize is the main crop grown on my home island - yellow maize used mostly for animal feed, but also enjoyed as sweet corn by many of the islanders. The major problem when growing maize is the damage caused by stem borers. These are the larvae of moths that hatch on the maize leaves and quickly burrow into the stems. Once inside the maize stalks the caterpillars are safe from predators and insecticide sprays. The caterpillars damage the food and water transport systems inside the stalks and then move into the young cobs where they eat the kernels and leave their droppings. Not only is this unpalatable for people, the damage to the maize tissue allows fungi to enter the maize plant and grow. The fungi are also protected from fungal sprays because they are inside the plant. In addition to causing mouldy kernels, the fungi produce toxins that are known to cause disease in animals and cancer in people.

The only way the island farmers have some control over the insects and fungi is to check daily for eggs on the undersides of the leaves. When they see moth eggs, the farmers need to spray within 24 hours to be sure to kill the larvae as they hatch or are on their way to the stalks. If this small window of opportunity is lost, no amount of insecticide will protect the crop. Daily checks are time consuming and can be easily overlooked on busy days or in very hot weather. For this reason, the farmers were excited to read of new technology in the United States that might offer better protection to the maize crop. Overseas seed companies had moved a gene from a soil bacterium into maize to give it a built-in protection against moth larvae. Farmers were growing the new 'Bt' corn with wonderful results. After some discussion the island farmers wrote to the US seed distributors and requested seed to grow on the island.

The seed distributor sent a letter back explaining that the Bt corn was produced by genetic modification (GM) and so had to have a biosafety assessment and approval from the island government before it could be imported. No one knew what this meant, so a few of the farmers called the island government and spoke to an official in the seed import division. He was aware of GM seeds and, although none had ever been imported into the country, he had a list of questions that needed to be asked to assess the safety of the seed for the island. He agreed to send the application form with the questions to the farmers for them to complete and submit for review.

The farmers had to contact the seed distributors for some of the answers to the questions, but within a few weeks were able to submit the application. On receiving the completed application from the farmers, the government asked local scientists to review the information and recommend whether the GM maize was safe for the people, animals, plants and environment of the island. The government also included trade, consumer and socioeconomic experts on the review team to look at these issues in relation to the island's needs.

Down:

Across:

Divide yourselves into review committees of not more than eight people and read the application.

Answer the questions below to help make recommendations to the island government.

If approval is recommended, are there any conditions thatthe farmers should implement to increase environmental safety?

If rejected, suggest what missing information is need before an approval could be recommended.

Questions:

1. Does the scientific evidence suggest that the Bt maize is safe for islanders and the environment? (Remember that environment means all living and non-living components, so don't forget the animals, microbes, plants, soil, water and air!)
2. Is there any evidence to suggest that the Bt maize will be of benefit to the island?
3. Is there any evidence to show that the Bt maize will harm the island in any way? (While this overlaps with question 1, look beyond safety issues to things like impact on jobs, trade, and quality of food and feed.)
4. Is there enough information to assess safety to humans and the environment?
5. What, if any, additional information would be useful to have a better understanding of the impact the GM maize will have on the island?
6. Can you suggest ways in which the missing information could be collected?
7. What concerns have anti-GM lobby groups raised about GM crops and foods?
8. Which of these concerns are relevant to the farmers' application?
9. What can be done to address the concerns of the anti-GM lobby groups?
10. What would your recommendation be to the government regarding this application? Would you approve it or suggest that approval be withheld? Give reasons for your recommendations.

The local farmers would like to import three genetically modified maize varieties from the United States to see if they are effective in controlling island stem borers and if the varieties are suited to the island environment. The testing will take one to three years. This will give time to see how well the varieties react to various natural levels of insect infection and various environmental pressures. If one or more of the varieties prove beneficial, the farmers will grow them in preference to conventional varieties.

The objective of this application is to obtain permission to import and test the Bt maize and see if it will offer the same benefits to the island that it is offering to farmers in North America, South America and Africa. If the Bt maize is effective against the island stem borers, it will enable farmers to have better control over these pests without the use of pesticides. The decrease in pesticide use will be good for the island's environment and people.

If the three available maize varieties are unsuited to island conditions, the farmers plan to test new varieties, as they become available. If the Bt maize does not control the island stem borer, the farmers will stop the tests and wait for varieties with new insect tolerance genes.

The maize varieties are all Zea mays, the same species that has been grown on the island for centuries. During this time the conventional maize has not had any recorded adverse effect on humans, plants, animals, soils, agriculture or the environment. Maize is not an invasive weed and is seldom found growing outside cultivated areas. When such plants are seen they are usually from seed that has dropped during transport from harvest to storage, or seed that has germinated in disused chicken runs. Farmers and the public collect these plants for animal feed.

The GM maize contains a gene from a soil bacterium that is found in soils all over the island. This gene makes a protein that is digested by most animal species, including humans, but is activated in the alkaline gut juices of a single group of insects, the lepidopterans. The lepidopterans are the moths and butterflies. This particular Bt protein does not affect all moths and butterflies, only those that have special attachment sites on their stomach walls. The Bt protein attaches to these sites and makes holes in the stomach wall.

A start sequence from a cauliflower virus and a stop sequence from a soil bacterium control the Bt gene. The control sequences are well studied and offer no health or environmental threat. The start sequence allows a very small amount of the Bt protein to be produced in all parts of the plant at all times. However, there is slightly more produced in young tissues than in old plant tissues.The maize varieties also contain a gene that protects them against herbicides that farmers use to kill weeds. This gene was used in the research and development phase of the genetic modification. This gene will not be used by the farmers, as the herbicide (weed killer) it protects against is not registered for use, or sold, on the island. This gene uses the same stop and start control sequences as the Bt gene and has been fully tested for human and animal safety. It offers a useful way to identify GM maize from conventional maize, if this is ever necessary.

In the 12 years that the Bt maize varieties have been grown around the world the genes have stayed stable. There is no evidence of the new genes moving in the plant, moving out of the plant, or switching off.Because people collect maize that germinates on its own, or it is eaten by free-range domestic animals, the GM maize is not expected to survive outside of cultivation. There are no known local relatives of maize on the island and no known plant species that cross-pollinate with maize. This is supported by observations over many years and a review of the island's plant species by botanists. The island does not produce enough maize to export and so it is unlikely that GM maize seed will leave the island. It will be possible to track the GM maize by using the herbicide tolerance gene. Small, research-size tests with the herbicide will quickly determine whether any seed or a plant is GM or conventional.

Initially it is planned to grow the GM maize on small areas of a few farms to see if it works against the island stem borer. The farmers will import enough seed for 1 hectare of maize in total and will spread this out between 3 or 4 sites. Only once one or more of the varieties prove effective, will more farmers grow more of the Bt maize. This is planned to ensure that the island does not suffer from a total crop failure should the GM seed prove unsuited to the island's environment. Also, should the new varieties prove more invasive, this will be easier to monitor from 3 to 4 small sites, than if the initial plantings take place all over the island.

Invasiveness

Invasiveness is the measure of how much a plant moves from its point of introduction into surrounding vegetation. The farmers undertake to watch for invasiveness of the GM maize. While this is unlikely to occur, because the herbicide gene will not be used, it will be important to check that the new genes do not make the Bt maize more invasive than conventional maize. The invasiveness will be monitored by routinely collecting leaf material from maize plants found outside the cultivation areas. These samples will be posted to the seed distributors for analysis. The study will look at whether the maize that moves away from the farms is mostly conventional or GM maize.

Harm to non-target insects

A major objection to growing Bt maize has been its potential affect on non-target insects like the Monarch butterfly. However, research has shown that the Monarch butterfly is not exposed to enough Bt pollen in nature to be affected. It is not certain which non-target insects might be affected on the island. To date, the only lepidopteran known to feed on maize is the stem borer. In addition, the effect of insecticide sprays on insect life is far worse than the effect of Bt maize: insect sprays kill all insects on and around the maize, but Bt maize only affects lepidopterans that feed on the plant.

Root exudates

There is concern that roots of Bt crops will release Bt protein into the soils and affect lepidopteran soil organisms. As Bt originates from soils and is already present in very high levels in soil bacteria, there is little support for this theory. Studies show that the maize Bt protein is rapidly broken down in soil environments.

Transfer of herbicide tolerant gene from dead plant material

Some concern has been raised that dead plant material will expose soil organisms to herbicide tolerant genes that could be taken up and spread in the environment. Scientists who have reviewed this risk see this as a highly unlikely scenario. The herbicide tolerant gene originally came from a soil organism that is present in very large numbers in the soil. As gene transfer is common between microorganisms and rare between microorganisms and plants, this transfer is much more likely to occur naturally than from the Bt crops. In addition, the maize material is collected at harvest and used for animal feed on the island, it is not ploughed in for compost.

Benefits observed by farmers growing Bt maize in other parts of the world include:

• A 70 to 90% decrease in insect damage compared to untreated maize;
• A 20 to 30% decrease in insect damage compared to maize sprayed with insecticides;
• A 60 to 70% decrease in the amount of insecticide used on Bt maize compared to conventional maize;
• A 90 to 95% decrease in fungal infections compared to untreated conventional maize;
• A 5 to 10% decrease in fungal infections compared to sprayed conventional maize;· A 12 to 28% decrease in input (chemicals, energy, equipment) costs;
• A considerable time saving in saved sprays;
• A general 'peace of mind' regarding stem borer infestations;
• Decreased pesticide applications to the food crop, benefit consumers;
• Less exposure to pesticides by people work on and living near the fields;
• Renewed ecology in Bt fields with a return of non-target insects, which has caused a return of birds and other animals.

Only by growing the Bt maize on the island, can we assess the actual benefits for the island's farmers, consumers and environment. After three years the farmers should have enough information to decide whether the GM maize is suitable and safe for the island.

Seeds

The cobs from the successful plantings will be used for animal feed and for humans. Some cobs will be sent to Botanists at the Botanical Gardens for analysis to see if there is any advantage to the island in reducing the amount of fungi affecting the maize. The cobs will be compared to conventional maize grown in the same area. This study needs to compare information from several seasons to give useful results.

Environmental pollution

The GM maize is unlikely to leave any residue or deposit any components on the island that will impact on the local environment. The Bt protein is only active against lepidopterans that feed on the maize and the protein is quickly inactivated in dead and composted material. While pollen may spread to other plants, field observations have not yet observed this to affect non-target insects, probably because the pollen is deposited in very small amounts and at a time when larvae are too old to be affected.

Public acceptance

The rejection of GM crops by consumers in Europe and other countries appears to be based on considerable misinformation distributed by the media. Scientists who review the safety of GM crops on a case-by-case basis are confident that approved GM foods are safe for the environment and for consumers. If the initial plantings of GM maize are successful it is planned to have a public hearing on the island to introduce the new crops and inform islanders of the risks and benefits. This meeting will discuss the safety information in detail in an attempt to give consumers confidence in the new crop. While there is no scientific reason to label Bt maize, labelling will be discussed at the meeting and the public recommendations reviewed by the farmers and food processors on the island.

Resistance development

There is concern that insects will develop resistance to the crop if exposed to it over a long period of time, as happens with other pesticides. This is true, and so resistance management strategies will be a condition of buying the seed. These strategies are easy to implement and have been successful in preventing resistance in other countries where up to 35% of the maize crop has Bt. No resistance has occurred to Bt crops worldwide in 6 years, because of the careful use of management strategies.

Divide into two groups: those in favour of the GI maize and those not in favour of introducing the GI maize. Prepare to debate the following:

Hold the debate this in the next lesson 'in front of a pubic meeting of islanders'.

The island government requires the farmers to put out pamphlets explaining the new GI maize and what impact this crop will have on the health and environment of the island. Work in editorial groups of six and prepare an A4 pamphlet for distribution among the islanders.

Biotechnology in livestock yields and quality

Every where I read about food production I also read about animal production. Meat is a popular food on our island. I was not surprised to see that biotechnology has been and is being used to improve meat as well as plants.

Species = the same type of organism. Usually distinguished by being able to mate.

Here we look at how genes are used in animal food production. Revise the opening paragraph in Study Unit 7, if you need background on genes, DNA and gene movement. The same breeding and selection processes are used for animals and modern genetic improvement allows scientists to move genes between different animal species.

The following passage comes from the Bible and is possibly the earliest record made of selection in livestock breeding:

Genesis 30:25-43

After Rachel gave birth to Joseph, Jacob said to Laban (his father-in-law), "Send me on my way so I may go back to my own homeland. Give me my wives and children, for whom I have served you, and I will be on my way. You know how much work I've done for you."

But Laban said to him, "If I have found favour in your eyes, please stay. I have learned by divination that the Lord has blessed me because of you." He added, "Name your wages, and I will pay them."

Jacob said to him, "You know how I have worked for you and how your livestock has fared under my care. The little you had before I came has increased greatly, and the Lord has blessed you wherever I have been. But now, when may I do something for my own household?"

"What shall I give you?" he asked.

"Don't give me anything," Jacob replied. "But if you will do this one thing for me, I will go on tending your flocks and watching over them. Let me go through all your flocks today and remove from them every speckled or spotted sheep, every dark-coloured lamb and every spotted or speckled goat. They will be my wages. And my honesty will testify for me in the future, whenever you check on the wages you have paid me. Any goat in my possession that is not speckled or spotted, or any lamb that is not dark-coloured, will be considered stolen."

"Agreed," said Laban. "Let it be as you have said." That same day he removed all the male goats that were streaked or spotted, and all the speckled or spotted female goats (all that had white on them) and all the dark-coloured lambs, and he placed them in the care of his sons. Then he put a three day journey between himself and Jacob, while Jacob continued to tend the rest of Laban's flocks.

Jacob, however, took fresh-cut branches from poplar, almond and plane trees and made white stripes on them by peeling the bark and exposing the white inner wood of the branches. Then he placed the peeled branches in all the watering troughs, so that they would be directly in front of the flocks when they came to drink. When the flocks were in heat and came to drink, they mated in front of the branches. And they bore young that were streaked or speckled or spotted. Jacob set aside the young of the flock by themselves, but made the rest face the streaked and dark-coloured animals that belonged to Laban. Thus he made separate flocks for himself and did not put them with Laban's animals. Whenever the stronger females were in heat, Jacob would place the branches in the troughs in front of the animals so they would mate near the branches, but if the animals were weak, he would not place them there. So the weak animals went to Laban and the strong ones to Jacob. In this way the man grew exceedingly prosperous and came to own large flocks, and maidservants and menservants, and camels and donkeys.

Although the passage refers to sticks in troughs used to select livestock, clearly what happened is that Jacob, being a brilliant livestock farmer, understood the genetics of selection very well. He was able to breed spotted, speckled and dark-coloured livestock from white livestock to create his own start-up flock. From then on, he was able to breed livestock using both his own stock and that of Laban, to build up a good strong flock of his own, all speckled, spotted or dark-coloured, earned honestly using selection techniques.

Laban later saw that Jacobs flocks were thriving and changed the deal often. He would say that only the speckled lambs could be Jacob's wages, and then Jacob would breed only speckled lambs. Then Laban would say only the spotted lambs could be his wages, and then all the lambs would be spotted. The name Laban means white and the whiteness on the sticks was a pun on Laban's name. This way Jacob was able to deceive Laban just as Laban had previously deceived Jacob.

In more recent history, when immigrant farmers used to arrive in a new country they would often arrive with some livestock from 'home'. These animals either fared well, or could not adapt to the new climate and environment. This points to an important fact about breeding and selection. While nature and breeders select for characteristics that suit a certain environment, the new herds may not be suited to all environments. A breed of goat or horse selected for its good qualities in Spain may be sensitive to disease or cold in another part of the world. For this reason, scientists are having a new look at indigenous domestic animals, e.g. the Nguni cattle of Southern Africa.

Consider and create a climate and environment for the island. Recommend what characteristics you would want in either a new milking herd or a new beef herd.

Hints:

A gene marker is a short piece of DNA that indicates that a certain characteristic is present in the organism. For instance, forensic scientists match blood from crime scenes to people by identifying certain specific markers found only in one person's genes.

Scientists have isolated three gene markers that show pigs will produce lean meat. You are a pig farmer on the island and want to focus your production of pork towards leaner, healthier meat. You send away hair samples from your latest litter and ask the researchers to identify which piglets have the lean meat markers. They return the following prints of DNA fragments but forget the analysis. Can you work out which piglet(s) to keep for breeding a lean meat litter?

L = the fragments from a lean pig; F = fragments from a fatty pig; 1 - 11 fragments for the new littler.Hint: Identify which fragments occur in the lean pig and not in the fat pig. See if any piglets have all of these exclusive fragments.