MCAT Biological and Biochemical Foundations of Living Systems: Passage 6 — Flashcards

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Family and twin studies have suggested that genetic factors could be responsible for 50% to 90% of the variation in bone mineral density (BMD). Therefore, a better understanding of these genes could lead to a more complete understanding of BMD, as well as osteoporosis, which is a condition caused by the loss of BMD and that leads to bone fragility with aging. Population-based case-control studies have identified polymorphisms in many candidate BMD genes. These studies have also highlighted genetic variability between Asian and Caucasian populations in at least five important osteoporosis candidate genes. To take a more extensive look at the genetic variability, researchers investigated single nucleotide polymorphisms (SNPs) in 81 genes associated with osteoporosis by sequencing across exons, splice junctions, and promoter regions. They analyzed these genes among 24 unrelated Korean individuals and compared them to previously reported SNPs in Japanese, Chinese, Caucasian, and African subpopulations. The researchers identified 942 variants, including 888 SNPs, 43 insertion/deletion polymorphisms, and 11 microsatellite markers. They determined whether some of the common SNPs in these subpopulations agree with or deviate from the Hardy-Weinberg principle, which states that genetic variation should remain constant between generations in the absence of factors such as natural selection and nonrandom mating. Further studies of osteoporosis could utilize the polymorphisms identified in this study since they may have important implications for the selection of highly informative SNPs for future association studies.