Question

genetically modified organisms click on the following links and browse through the information: http://www.biology - online.org/2/12_selective_breeding.htm http://www.direwolfproject.com/selective - breeding.html http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/living/genesrev1.shtml answer the following questions: when two organisms are selectively bred together are the parents homozygous recessive, heterozygous, or homozygous dominant for the traits being selected for? list two pros of selective breeding. list two cons of selective breeding. how long have humans been selectively breeding animals and plants? go to the following site: www.monsanto.com pick an article - either from the front page or by searching a topic that is interesting to you. write a summary of the article. investigate the development of gmos through selective breeding or through gene manipulation in the laboratory click on the following link: http://www.pbs.org/wgbh/harvest/engineer/ try going through both the selective breeding and the gene manipulation tutorials located on the right side of the page. write notes on the steps you take through the tutorials. answer the following questions: for selective breeding: how many generations did it take before you got to the optimum crop? what are the negatives for this type of plant breeding? for gene manipulation: what is a vector? what gene besides bt has been added to the vector? why might there need to be two different growth medias? what is the purpose of \spraying\ the plant growth media with herbicide? why will herbicide determine which plants contain the correct gene? click on the following link. this link will take you through a brief review of 12 different cases for gmo crops, and ask whether you think we should grow them. http://www.pbs.org/wgbh/harvest/exist/ after reading each case, click on your answer basing your opinion off of each case alone. at the end record how many yes and no answers you gave. write a statement telling how you answered for at least 2 cases. explain your reasoning. click on the what’s for dinner link: http://www.pbs.org/wgbh/harvest/coming/

Explanation:

1. When two organisms are selectively bred, the parents can be any of homozygous recessive, heterozygous, or homozygous dominant depending on the traits and breeding goals. For example, if aiming to fix a recessive - desired trait, homozygous recessive parents might be used.
2. Pros of selective breeding:

• Can improve desired traits like higher yield in crops or better milk - production in cows.
• Can preserve genetic diversity within a species by carefully choosing breeding pairs.

1. Cons of selective breeding:

• Can lead to inbreeding depression if closely related individuals are repeatedly bred, increasing the risk of genetic disorders.
• Reduces genetic variation over time as only certain traits are selected for.

1. Humans have been selectively breeding animals and plants for thousands of years, starting from the dawn of agriculture around 10,000 - 12,000 years ago.
2. For the article summary from monsanto.com, this would depend on the specific article chosen. However, in general, articles on such a site might discuss the development of GMOs, their benefits (such as increased crop resistance to pests or tolerance to herbicides), and their potential impact on agriculture.
3. For selective breeding in tutorials: The number of generations to reach an optimum crop can vary widely depending on the trait and the species, often ranging from several to many generations. Negatives include the long time - consuming process and the potential for inbreeding.
4. For gene manipulation: A vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed. The specific gene besides Bt added to a vector depends on the experiment's goals. Two different growth media might be needed to first grow bacteria containing the vector and then to grow plant cells for transformation. Spraying the plant growth media with herbicide is a way to select for plants that have incorporated the desired gene, as the gene often confers herbicide - resistance.
5. For the GMO cases on pbs.org, responses will vary based on individual opinions. For example, if considering a GMO crop that is resistant to a particular pest, one might answer yes if they think it can reduce pesticide use and increase food security, or no if they are concerned about potential impacts on non - target organisms.

Answer:

1. Can be homozygous recessive, heterozygous, or homozygous dominant.
2. Higher yield in crops; preservation of genetic diversity.
3. Inbreeding depression; reduction of genetic variation.
4. Around 10,000 - 12,000 years.
5. Varies based on the article chosen.
6. Varies for number of generations; long - time consuming and inbreeding potential for negatives.
7. A vector is a DNA molecule for carrying foreign genetic material; depends on the experiment for other genes; to grow different cell types; to select for plants with the desired gene.
8. Varies based on individual opinions for each case.