Select some particular plant or animal and find out how it has been improved because of the study of genetics. The following examples are given, but you may select some other topic if you like. Be sure that you have the topic and the method (written or oral) of reporting approved before you do your research. If you choose an oral report, it should be at least 3 minutes in length. If you choose a written report it should be at least 500 words in length. Do some research into thornless varieties of plants.
What plants are available which do not have thorns?
Is thornlessness a mutation?
When and where was the possibility of growing thornless varieties of plants discovered?
How do these varieties compare with the variety that has thorns?
Consult seed catalogs, gardening books, and magazines in the library.
Do some research into the new variety of pumpkins that do not have hulls on their seeds.
Is the flavor of the new variety as good as the flavor of the older varieties, or is the new variety raised only to have seeds without hulls?
How are the seeds prepared?
Is the pumpkin seed a good source of protein?
Consult seed catalogs, gardening books, and gardening magazines.
Study the potato famine in Ireland.
Study how the use of some modern types of potatoes can help to overcome such famines.
Give some examples of potatoes which are hardy against disease.
Study the careful breeding experiments that resulted in disease resistant potatoes.
What makes them hardier and more disease resistant?
What makes them hardier and more disease resistant?
Do some research to find out about the new breeds of cattle that provide much better beef than the older breeds.
Consult a genetics book from the library to determine the names of such cattle.
what makes these breeds better? Are they cared for the same way? Do they have any drawbacks in terms of cost of breeding and raising?
You may want to investigate some of the diseases which are inherited.
Consult a genetics textbook from the library.
You may also need to look up some of these in a medical textbook or the Journal of Heredity.
Who is more likely to inherit them? Why?

BACKGROUND

Modification to produce desired traits in plants, animals, and microbes used for food began about 10,000 years ago. These changes, along with natural evolutionary changes, have resulted in common food species that are now genetically different from their ancestors.

Advantageous outcomes of these genetic modifications include increased food production, reliability, and yields; enhanced taste and nutritional value; and decreased losses due to various biotic and abiotic stresses, such as fungal and bacterial pathogens. These objectives continue to motivate modern breeders and food scientists, who have designed newer genetic modification methods for identifying, selecting, and analyzing individual organisms that possess genetically enhanced features.

For plant species, it can take up to 12 years to develop, evaluate, and release a new variety of crop in accordance with international requirements, which specify that any new variety must meet at least three criteria: it must be genetically distinct from all other varieties, it must be genetically uniform through the population, and it must be genetically stable (UPOV, 2002).

While advances in modification methods hold the potential for reducing the time it takes to bring new foods to the marketplace, an important benefit of a long evaluation period is that it provides opportunities for greater assurance that deleterious features will be identified and potentially harmful new varieties can be eliminated before commercial release. As discussed more fully in Chapter 5, it is both prudent and preferable to identify potentially hazardous products before they are made commercially available, and with few exceptions standard plant breeding practices have been very successful in doing so.

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PLANT GENETIC MODIFICATION

Techniques Other than Genetic Engineering

Simple Selection

The easiest method of plant genetic modification (see Operational Definitions in Chapter 1), used by our nomadic ancestors and continuing today, is simple selection. That is, a genetically heterogeneous population of plants is inspected, and “superior” individuals—plants with the most desired traits, such as improved palatability and yield—are selected for continued propagation. The others are eaten or discarded. The seeds from the superior plants are sown to produce a new generation of plants, all or most of which will carry and express the desired traits. Over a period of several years, these plants or their seeds are saved and replanted, which increases the population of superior plants and shifts the genetic population so that it is dominated by the superior genotype. This very old method of breeding has been enhanced with modern technology.

An example of modern methods of simple selection is marker-assisted selection, which uses molecular analysis to detect plants likely to express desired features, such as disease resistance to one or more specific pathogens in a population. Successfully applying marker-assisted selection allows a faster, more efficient mechanism for identifying candidate individuals that may have “superior traits.”

Superior traits are those considered beneficial to humans, as well as to domesticated animals that consume a plant-based diet; they are not necessarily beneficial to the plant in an ecological or evolutionary context. Often traits considered beneficial to breeders are detrimental to the plant from the standpoint of environmental fitness. For example, the reduction of unpalatable chemicals in a plant makes it more appealing to human consumers but may also attract more feeding by insects and other pests, making it less likely to survive in an unmanaged environment. As a result, cultivated crop varieties rarely establish populations in the wild when they escape from the farm. Conversely, some traits that enhance a plant's resistance to disease may also be harmful to humans.

credit to https://www.ncbi.nlm.nih.gov/books/NBK215771/

consider the reaction below.

 no rx

at 500 k, the reaction is at equilibrium with the following concentrations.

[pci5]= 0.0095 m

[pci3] = 0.020

[ci2] = 0.020 m

what is the equilibrium constant for the given reaction?

0.042

0.42

2.4

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