HHMI - Evolution of Lactose Tolerance

What is the main sugar in milk that needs to be broken down for digestion?

• Galactose

• Glucose

• Lactose

• Maltose

What typically happens when an adult mammal, other than a lactase-persistent human, consumes milk?

• The milk is fully digested and absorbed for energy.

• The undigested lactose travels to the large intestine, causing digestive issues.

• The lactose is broken down into glucose and galactose in the small intestine.

• The mammal develops an increased ability to produce lactase.

What does it mean for a human to be "lactase persistent"?

• They are unable to digest lactose as an adult.

• Their body continues to produce the lactase enzyme beyond childhood.

• They can only digest milk from specific animal species.

• They experience severe digestive issues after consuming milk.

What did researchers discover about the genetic basis of lactase persistence in Europeans and the Maasai?

• A single, universal mutation is responsible for lactase persistence across all populations.

• Lactase persistence is caused by different, independently evolved mutations in different populations.

• The ability to digest lactose is not genetically determined.

• Lactase persistence is only found in populations that traditionally consumed dairy.

What common characteristic did the Maasai and early Europeans share that might explain their independent evolution of lactase persistence?

• They were primarily hunter-gatherers.

• They were pastoralists who domesticated animals for food.

• They lived in similar geographical regions.

• They had a shared genetic ancestry.

How did Richard Evershed determine if ancient pots once held milk?

• By analyzing the pottery's color and texture.

• By examining the shape and size of the pots.

• By identifying chemical signatures of milk fats trapped in the pottery.

• By comparing the pots to modern milk containers.

What was a significant selective advantage of lactase persistence, especially during times of famine?

• It allowed individuals to consume more meat.

• It provided a safe and nutritious food source when other crops failed.

• It improved resistance to common diseases.

• It led to increased physical strength.

What term describes the unique relationship between human biological evolution and cultural practices, such as dairying?

• Genetic drift.

• Natural selection.

• Gene-culture coevolution.

• Cultural assimilation.

How is the story of lactase persistence in humans similar to the story of the dark fur trait in Rock Pocket mice?