Name: ________________________________________________
Date: _________
Period: _________
HS Biology Unit 1 Mini-Lesson I: Can a parent's environment during
pregnancy affect their grandchildren?
1. Read and annotate the introductory paragraphs below. As
part of your annotations, mark up the text with at least 3
questions you have about the case study history and two
different theories proposed.
While we now know much about the inheritance of traits, as recently
as the 1800s much of this branch of science was still a mystery.
One prominent theory at the time came from Jean-Baptiste Lamarck
who believed that events that occurred during the lifetime of an
organism could have an effect on the traits of its offspring. For example, someone who spends their life lifting
weights and building up muscle mass would likely give birth to a very fit and muscular child. While the image of
a body builder baby is certainly amusing, Lamarckian evolution was largely discredited by later discoveries.
Many recent studies however have indicated that some such scenarios could exist.
Recent studies suggest that environmental stresses in a parent may harm the health of subsequent
generations including grandchildren. One example includes parents who were pregnant during a 1944 famine
in the Netherlands known as the Dutch Hunger Winter had children and grandchildren who were unusually
small or prone to diabetes and obesity. Scientists were puzzled by this observation and competing
mechanisms for this phenomenon have been developed. Below are the two proposed mechanisms of how the
Dutch Hunger Winter affected the children and grandchildren:
●
Proposed Mechanism 1: Perhaps the Dutch Hunger Winter caused inheritable changes to the DNA
and genes of fetuses born to starving parents, which made the certain genes less active — and
continued to do so for life. As a result, less of the protein coded for by an affected gene is made, and
metabolism slows down.
●
Proposed Mechanism 2: Dutch famine probably led to many miscarriages and early deaths. It’s
possible that the survivors had some genetic variant that made them resilient and gave them a
distinctive genetic profile.
HS Biology | Unit 1 Mini Lesson I
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Name: ________________________________________________
Date: _________
Period: _________
Dataset 1
DNA methylation refers to changes in the structure (and therefore
function) of DNA that can happen during an individual’s lifetime.
Scientists evaluated whether DNA methylation in the blood of pregnant
parents during times of famine could cause changes to the genes and
traits of their unborn children.
Data table 1 looks at several health
conditions experienced by adults who were
in utero (still in the parent’s womb) during the
Dutch Hunger Winter. The “famine exposure”
group were people who were in utero during
the time period of the Dutch Hunger Winter
and whose parents were affected by famine,
while the “control” group were in utero during
the same time period but whose parents
were unaffected by the famine conditions.
BMI, or Body Mass Index, is an indicator of
the percentage of a person’s mass that is
made up of fat. Triglyceride levels measure
the amount of fat in a person’s blood, and
glucose baselines are a measure of resting
blood sugar. In general, higher levels of all
three values are risk factors for poor health.
Data table 2 takes individuals from the trail
who were exposed to famine and/or who
showed high levels of BMI. They analyzed
the probability that one of three genes
involved in metabolism was found to be
methylated because of either famine or the
increased BMI. In the case that a methylated
gene was likely to be found in both the
famine and increased BMI groups (like
CRELD 2), it is assumed that famine caused
the gene to become methylated and
therefore wrongly inactivated which then led
to an increased BMI.
HS Biology | Unit 1 Mini Lesson I
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Name: ________________________________________________
Date: _________
Period: _________
2. Which proposed mechanism does data set 1 best support? In your response, cite specific evidence
from the data.
Dataset 2
In order to test the theory that
exposure to famine increased the
likelihood of several negative
pregnancy outcomes, phone interviews
were conducted of over a thousand
people who experienced the famine.
These interviews took place over 50
years after the Dutch Hunger Winter.
Selected measures of reproductive
function among 1070 people who
participated in the telephone interview
of the Hunger Winter Family Study are organized in the table by recruitment category.
3. Which proposed mechanism does data set 2 best support? In your response, cite specific evidence
from the data.
HS Biology | Unit 1 Mini Lesson I
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Name: ________________________________________________
Date: _________
Period: _________
Dataset 3
Why parent’s bodies abort males during tough times
By Elizabeth Pennisi Dec. 11, 2014 , 3:00 PM
In times of trouble, multiple studies have shown,
more girls are born than boys. Biologists have long
thought that the parent spontaneously aborts male
fetuses that are frail, making room for new
pregnancies and, possibly, a healthier baby.
(Females are thought to have a better chance of
reproducing than males in tough times, so aborting
them doesn’t make as much evolutionary sense.)
Because of the large investment required to raise
children, “there would be a big payoff to being able
to select which fetuses to raise and which not,” says
Ron Lee, an economic demographer at the University of California (UC), Berkeley.
The researchers at the University of Sheffield looked at the sex ratios of newborns from 1790 through 1870 and
tallied how many males survived infancy, an indication of how healthy the fetus was, and how many children
they subsequently had that in turn reached puberty. They found 16 years where the percentage of male infants
surviving plunged, with one in the late 18th century dropping to 79 males for every 100 females. The finding
“offers further confirmation of the suspicions that male [fetuses] are more vulnerable to miscarriage than
females and that the aborted fetuses are frail.”
The researchers don’t yet know the stress, such as hunger, that may have been experienced by pregnant
parents in those unusual years. Still, these data show that “the ambient environment during pregnancy shapes
the quality of the males over their lifetime,” Bruckner says. In general men die 5 or 6 years earlier than women.
“We’re trying to understand the causes of gender imbalance in life span and what contributes to the variance”
in how long individuals live, he adds. Pinpointing what happens to frail males in utero is a first step in that
direction.
4. Which proposed mechanism does data set 3 best support? In your response, cite specific evidence
from the data.
HS Biology | Unit 1 Mini Lesson I
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Name: ________________________________________________
Date: _________
Period: _________
5. Compare and evaluate the two proposed mechanisms and determine which of them is best supported
by data sets 1, 2, and 3. In your explanation, incorporate data from all three sources. Additionally,
describe any limitations, constraints, or ethical issues involved in the collection of any data sets.
Sources:
Introduction:
● Kaiser, J. (2014). Mom’s environment during pregnancy can affect her grandchildren. Science. July, 10.
● Zimmer, C. (2018). The famine ended 70 years ago, but Dutch genes still bear scars. The New York
Times, 31(1).
Dataset 1:
● Tobi, E. W., Slieker, R. C., Luijk, R., Dekkers, K. F., Stein, A. D., Xu, K. M., ... & Biobank-based Integrative
Omics Studies Consortium. (2018). DNA methylation as a mediator of the association between prenatal
adversity and risk factors for metabolic disease in adulthood. Science advances, 4(1), eaao4364.
Dataset 2:
● Yarde, F., Broekmans, F. J. M., Van der Pal-de Bruin, K. M., Schönbeck, Y., Te Velde, E. R., Stein, A. D., &
Lumey, L. H. (2013). Prenatal famine, birthweight, reproductive performance and age at menopause: the
Dutch hunger winter families study. Human Reproduction, 28(12), 3328-3336.
Dataset 3:
● Pennisi, E. (2017, December 10). Why women's bodies abort males during tough times. Retrieved from
https://www.sciencemag.org/news/2014/12/why-women-s-bodies-abort-males-during-tough-times
HS Biology | Unit 1 Mini Lesson I
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Name: ________________________________________________
HS Biology | Unit 1 Mini Lesson I
Date: _________
Period: _________
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