print Monoculture and the Irish Potato Famine: cases of missing genetic variation
Lumpers
In the 1800s, the Irish solved their problem of feeding a growing population by planting potatoes. Specifically, they planted the "lumper" potato variety. And since potatoes can be propagated vegetatively, all of these lumpers were clones, genetically identical to one another.
The lumper fed Ireland for a time, but it also set the stage for human and economic ruin. Evolutionary theory suggests that populations with low genetic variation are more vulnerable to changing environmental conditions than are diverse populations. The Irish potato clones were certainly low on genetic variation, so when the environment changed and a potato disease swept through the country in the 1840s, the potatoes (and the people who depended upon them) were devastated.
The importance of diversity
The genetically identical lumpers were all susceptible to a rot caused by Phytophthora infestans, which turns non-resistant potatoes to inedible slime. Because Ireland was so dependent on the potato, one in eight Irish people died of starvation in three years during the Irish potato famine of the 1840s.
Although the famine ultimately had many causes, the disaster would likely not have been so terrible had more genetically variable potatoes been planted. Some potatoes would have carried the right genes to make it through the epidemic, and more of the resistant varieties could have been planted in the years following the first epidemic. Later, scientists identified resistance genes in a potato from South America, where farmers have preserved the genetic variation of potatoes by growing many cultivated varieties alongside the potato's wild cousins.
The image below compares the effect of a blight on diverse and cloned crops.
print Monoculture and the Irish Potato Famine: cases of missing genetic variation
Lumpers
In the 1800s, the Irish solved their problem of feeding a growing population by planting potatoes. Specifically, they planted the "lumper" potato variety. And since potatoes can be propagated vegetatively, all of these lumpers were clones, genetically identical to one another.
The lumper fed Ireland for a time, but it also set the stage for human and economic ruin. Evolutionary theory suggests that populations with low genetic variation are more vulnerable to changing environmental conditions than are diverse populations. The Irish potato clones were certainly low on genetic variation, so when the environment changed and a potato disease swept through the country in the 1840s, the potatoes (and the people who depended upon them) were devastated.
The importance of diversity
The genetically identical lumpers were all susceptible to a rot caused by Phytophthora infestans, which turns non-resistant potatoes to inedible slime. Because Ireland was so dependent on the potato, one in eight Irish people died of starvation in three years during the Irish potato famine of the 1840s.
Although the famine ultimately had many causes, the disaster would likely not have been so terrible had more genetically variable potatoes been planted. Some potatoes would have carried the right genes to make it through the epidemic, and more of the resistant varieties could have been planted in the years following the first epidemic. Later, scientists identified resistance genes in a potato from South America, where farmers have preserved the genetic variation of potatoes by growing many cultivated varieties alongside the potato's wild cousins.
The image below compares the effect of a blight on diverse and cloned crops.
bla bla bla............etc.
So, we need diverse immigration so the old WASP folks interbreed with healthy young immigrants and produce a stronger people....................Lest we rot like the potato, or die out like the fellas on that island with all the big rocks standing around.
Make sense? Goddam right.!!! I volunteer to start the breeding program today. Line up on the right please. Or the left.
