Within European and populations of European ancestry, they are almost entirely correlated with the presence of
the −13,910 C/T mutation in the enhancer region of
the lactase gene (LCT).
Is there only one mutation that causes lactase persistence?
Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (
−13910*T
) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East.
How did lactase persistence arise in humans?
The story turned out to be that
changes in food production practices during the Neolithic revolution
(approximately 10,000 years ago, when human populations began domesticating various plants and animals) led to an increase in the frequency of genetic variants that maintain the expression of lactase in adulthood.
Why would a mutation leading to lactase persistence?
The lactase-persistence mutation would become common if
it provided a survival and reproductive advantage in a particular environment
. For example, in a population with domesticated cows, where milk is available, the ability to drink milk might have been advantageous in periods of drought or when food was limited.
Is lactase persistence genetic?
In other healthy humans, lactase activity persists at a high level throughout adult life, enabling them to digest lactose as adults. This
dominantly inherited genetic trait
is known as lactase persistence.
How is lactase persistence an example of human evolution quizlet?
How is lactase persistence an example of human evolution?
The ability to digest milk is a recently derived trait
. This means until very recently, we weren’t able to digest milk. Therefore, we had to evolve to be able to digest milk.
When did humans become lactose tolerant?
The pattern was the same for all mammals: At the end of infancy, we became lactose-intolerant for life. Two hundred thousand years later,
around 10,000 B.C.
, this began to change. A genetic mutation appeared, somewhere near modern-day Turkey, that jammed the lactase-production gene permanently in the “on” position.
Is lactose tolerance a mutation?
Thousands of years ago,
a mutation in the human genome allowed many adults to digest lactose and drink milk
.
What did researchers discover about genetic mutations that cause lactase persistence group of answer choices?
The practice of dairying provided an environment
in which lactase persistence was advantageous. D. Different mutations can produce the same phenotype. Scientists have identified distinct mutations among northern Europeans and the Maasai people of eastern Africa that resulted in lactase persistence.
How do mutations occur?
Mutations can result from
DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses
. Germ line mutations occur in the eggs and sperm and can be passed on to offspring, while somatic mutations occur in body cells and are not passed on.
Why is lactase persistence an example of convergent evolution?
Once the lactase persistence trait evolved, it quickly spread across northern Europe.
A separate independent mutation to the same regulatory DNA region conferred lactase persistence to at least one culture of humans living in Africa
(e.g., convergent evolution).
What is lactase persistence quizlet?
– lactase is an enzyme that breaks lactose, the main sugar in milk, into glucose and galactose. what is the function of lactase on your body? – breaks down lactose, which is found in milk. define lactase persistence. –
the ability to produce lactase and digest lactose.
Why is lactase persistence called co evolution of genes and culture?
In other words, genes and cultures coevolve. Lactase persistence,
the ability to digest lactose and therefore to drink fresh milk after the nursing period
, exemplifies the process of gene-culture coevolution. … Older children and adults have lactose intolerance and are unable to consume fresh milk.
Where is lactase persistence common?
Lactase persistence is common in people
of European ancestry as well as some African, Middle Eastern and Southern Asian groups
, but is rare or absent elsewhere in the world.
What would be an effect of a mutation in the coding region of the lactase gene?
The mutations are believed to interfere with the function of the lactase enzyme,
leading to undigested lactose in the small intestine and causing severe diarrhea
. Lactose intolerance in adulthood is caused by gradually decreasing activity (expression) of the LCT gene after infancy, which occurs in most humans.
What did researchers discover about the genetic mutation?
Researchers at The Feinstein Institutes for Medical Research, in collaboration with Columbia University, have identified a gene mutation that could result in schizophrenia, a chronic brain disorder that affects nearly one percent of the world’s population.
How would a biologist describe someone who is lactase persistent?
A lactase-persistent person is
lactose tolerant
. Four individuals measured their baseline blood glucose, then drank a litre of milk.
In what part of the world did the mutation for lactose tolerance first appear?
The genetic mutation conferring this advantage—shared by most lactose tolerant Europeans—was commonly thought to have occurred first in
the northern part of the continent
, where the sun shines less and people may be in greater need of the vitamin D found in cow’s milk.
Which discovery supports the hypothesis that evolution of the lactase persistence trait was driven by the use of milk in cultures that domesticated cattle?
Humans are still evolving and will continue to evolve through natural selection. Which discovery supports the hypothesis that evolution of the lactase persistence trait was driven by the use of milk in pastoralist cultures?
Ancient pots used to hold milk are about the same age as the lactase persistence mutations
.
Why do you think that some populations developed lactase persistence quizlet?
Lactase persistance in humans is caused by
specific mutations in a DNA control region
. … The frequency of the alleles that cause lactase persistence increased in some human populations over time. As a result, the frequency of lactase persistence in the population also increased.
How a mutation can give adults the ability to digest milk?
Adults who can digest lactose have a
DNA mutation
that keeps the bookmark in place. They can still make lactase and digest milk. Now diet won’t affect any of this. Scientists thought previously that being able to drink milk was a “use it or lose it” phenomenon.
Do all human individuals who are lactose persistence have the same genetic mutation?
However,
not all
genetically lactase nonpersistent individuals are noticeably lactose intolerant, and not all lactose intolerant individuals have the lactase nonpersistence genotype.
Which discovery supports the hypothesis that evolution of lactase persistence was caused by the use of milk in pastoralist cultures?
Which discovery supports the hypothesis that evolution of the lactase persistence trait was driven by the use of milk in pastoralist cultures?
Ancient pots used to hold milk are about the same age as the lactase persistence mutations
.
What enzyme is lactase?
Lactase is an enzyme.
It breaks down lactose, a sugar in milk and milk products
. Some people’s bodies do not make enough lactase, so they are not able to digest milk well, which can lead to diarrhea, cramps, and gas. This is referred to as “lactose intolerance.” Taking supplemental lactase can help break down lactose.
Which individuals show evidence of lactase persistence?
Which individuals appear to be lactase persistent? Use data to support your answer.
Lisa and Brian
are lactase persistent. The hydrogen breath test results from these two individuals suggest that the level of hydrogen in their breath does not increase significantly.
What are the 4 types of mutation?
- Germline mutations occur in gametes. Somatic mutations occur in other body cells.
- Chromosomal alterations are mutations that change chromosome structure.
- Point mutations change a single nucleotide.
- Frameshift mutations are additions or deletions of nucleotides that cause a shift in the reading frame.
How does the lactase enzyme work quizlet?
Lactase is an enzyme that
breaks down lactose into galactose and glucose
. If a person’s body produces lactase, then they can break down lactose, which makes them lactose tolerant. If a person’s body does not produce lactase, then they cannot break down lactase and, therefore, are not lactose tolerant.
Where is lactase usually found quizlet?
2. Brush border enzymes such as Maltase, Lactase and Sucrase are found in
the small intestine on the microvilli
and they convert disaccharides into monosaccharides.
What is the main function of lactose quizlet?
Breaking apart the disaccharide lactose molecule into two monosaccharide molecules makes it possible for
the body to digest a milk product
.
What are 3 causes of mutations?
- Mutations are caused by environmental factors known as mutagens.
- Types of mutagens include radiation, chemicals, and infectious agents.
- Mutations may be spontaneous in nature.
What is genetic mutations in humans?
Genetic mutation is
a permanent change in the DNA
. Mutations may or may not produce changes in the organism. Hereditary mutations and Somatic mutations are the two types of Gene mutations.
Is there only one mutation that causes lactase persistence?
Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (
−13910*T
) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East.
