Major gene pool centers | Biogeography | Principle Of Geography

 

Biogeography

Principle Of Geography

Geography Complete Study Material

(Paper - I)

Major Gene pool Centers

            The combination of all the genes present in a given population is called the gene pool of that population. It represents the complete genetic diversity found within a population or species. Gene Pool Centers refers to areas on the earth where important crop plants and domestic animals originated. They have an extraordinary range of the wild counterparts of cultivated plant species and useful tropical plants. Gene pool centres also contain different subtropical and temperate region species.

       Gene pool centers refers to areas on the earth where important crop plants and domestic animals originated. They have an extraordinary range of the wild counterparts of cultivated plant species and useful tropical plants. Gene pool centres also contain different sub-tropical and temperate region species.

Major Gene Centres:

           In 1926 he published “Studies on the Origin of Cultivated Plants” which described his theories on the origins of crops. Vavilov concluded that each crop has a characteristic primary center of diversity which is also its center of origin. Eight areas were recognized and suggested as centers from which all of our major crops were domesticated. Later, he modified his theory to include “secondary centers of diversity” for some crops.

1) Mediterranean Gene Centre: Existed around 4000BC

2) South American Gene Centre: Domestication of Plants seems to have taken place around 7000-3000BC

3) South West and Middle East: Evidence show plant domestication to have taken place during 8000-6000 BC

4) African Gene Centre: Primarily around Nile River –Plants and Animals were domesticated around 5000 BC.

5) South American and Central American –Developed around 3500 BC

6) Indian Gene centre:

1.  A) Indus
2.  B) South Asian: Includes Pakistan, Bangladesh, Sri Lanka, Myanmar

7) Central Asian Gene centre: Developed around 4000BC-3000BC

8) East Asia Gene centres: Develop around 6000-5000 BC.

Importance of preserving Gene Pool:

• Gene pool represents the total number of genes found within a population, those populations with larger gene pools tend to have more genes, and hence, more genetic diversity. Each gene has a specific purpose, such as giving the plant/animal a particular characteristic, resistance to a disease, tolerance to harsh climate, and so on. Therefore, a population with a larger genetic diversity will be better prepared to deal with disease outbreaks or extreme environmental changes, because they will, most likely, have those genes that protect them from such adverse changes. On the other hand, populations with a lesser number of genes in their gene pool will be susceptible to such problems, which may cause them to become endangered or even perish altogether, i.e., become extinct. Therefore, populations with a large gene pool will have more chances of survival, while those with small gene pools are in danger of acquiring genetic diseases, deformities, and infertility.
• Each gene has a specific purpose, such as giving the plant/animal a particular characteristic, resistance to disease, tolerance to the harsh climate, and so on. Therefore, a population with a larger genetic diversity will be better prepared to deal with disease outbreaks or extreme environmental changes, because they will, most likely, have those genes that protect them from such adverse changes.
• FAO estimates that in the last century, about 75 percent of crop genetic diversity was lost as farmers worldwide switched to genetically uniform, high-yielding varieties and abandoned multiple local varieties.
• Gene pool represents the total number of genes found within a population, those populations with larger gene pools tend to have more genes, and hence, more genetic diversity.

Thus gene pool conservation is important for sustainable development. Having recourse to genetic material is however essential to adapt and improve agriculture in the face of threats, such as diseases or warming climate that can alter growing conditions. For example, a variety of Turkish wheat, collected and stored in a seed gene bank in 1948, was rediscovered in the 1980s, when it was found to carry genes resistant to many types of disease-causing fungi. Plant breeders now use those genes to develop wheat varieties that are resistant to a range of diseases.