GRE General Test Practice Questions - Graduate Record Examinations General Test Exam

Read the passage and answer the question. "Epigenetics—the study of heritable changes in gene expression that do not involve alterations to the underlying DNA sequence—has unsettled the strict Mendelian framework that dominated genetics for much of the twentieth century. While Mendel's laws elegantly explain the transmission of discrete traits via alleles, they cannot account for phenomena such as genomic imprinting, where a gene's expression depends on which parent contributed it, or for the silencing of genes by methyl groups added to DNA strands. Critics of epigenetics' more ambitious claims, however, caution that many epigenetic marks are reset between generations and that the field sometimes overstates the heritability of environmentally acquired traits." The author's attitude toward epigenetics can best be described as: