Both men and women conceived during the widespread famine of the Dutch Hunger Winter were more likely to be obese by age 5050 an
d more likely to die from stroke or cardiovascular disease. They also experienced more cognitive decline later in life. Fifteen genetic loci associated with growth and metabolic disease were compared between siblings prenatally exposed to the famine and those siblings who were not prenatally exposed. 1. What evidence suggests that these are epigenetic effects?
a. missense mutations within genes encoding histone proteins
b. single nucleotide polymorphisms within loci involved in growth and metabolic disease
c. transposon insertion into loci involved in growth and metabolic disease
d. changes in the methylation patterns of loci involved in growth and metabolic disease
2. Which additional pieces of evidence would help to demonstrate that these effects are due to epigenetic changes?
a. changes in the post-translational modification of metabolic enzymes
b. differences in the expression of metabolic genes
c. mutations in the DNA regions associated with cardiovascular health
d. changes in histone acetylation patterns
1. d. changes in the methylation patterns of <em>loci</em> involved in growth and metabolic disease
2. b. differences in the expression of metabolic genes
d. changes in histone acetylation patterns
Explanation:
Epigenetics refers to the study of heritable changes in gene expression which are not dependent on DNA sequence. Epigenetic mechanisms involve DNA methylation, histone modifications (acetylation, methylation, phosphorylation, etc) and regulatory non-coding RNA (ncRNA) pathways. These epigenetic mechanisms work together and mutually reinforce each other in order to modulate gene expression (either by activating or suppressing gene expression). In consequence, transcriptome data (e.g., genes differentially expressed in particular tissues/cells or stages of development) is an important piece of evidence indicating the existence of epigenetic modulation.
Glaciers act as reservoirs of water that persist through summer. Continual melt from glaciers contributes water to the ecosystem throughout dry months, creating perennial stream habitat and a water source for plants and animals. The cold runoff from glaciers also affects downstream water temperatures.
