Elizabeth Norgard

Publications (2)5.77 Total impact

• Article: Replication of long-bone length QTL in the F9-F10 LG,SM advanced intercross.

  Elizabeth A Norgard, Joseph P Jarvis, Charles C Roseman, Taylor J Maxwell, Jane P Kenney-Hunt, Kaitlin E Samocha, L Susan Pletscher, Bing Wang, Gloria L Fawcett, Christopher J Leatherwood, Jason B Wolf, James M Cheverud
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  ABSTRACT: Quantitative trait locus (QTL) mapping techniques are frequently used to identify genomic regions associated with variation in phenotypes of interest. However, the F(2) intercross and congenic strain populations usually employed have limited genetic resolution resulting in relatively large confidence intervals that greatly inhibit functional confirmation of statistical results. Here we use the increased resolution of the combined F(9) and F(10) generations (n = 1455) of the LG,SM advanced intercross to fine-map previously identified QTL associated with the lengths of the humerus, ulna, femur, and tibia. We detected 81 QTL affecting long-bone lengths. Of these, 49 were previously identified in the combined F(2)-F(3) population of this intercross, while 32 represent novel contributors to trait variance. Pleiotropy analysis suggests that most QTL affect three to four long bones or serially homologous limb segments. We also identified 72 epistatic interactions involving 38 QTL and 88 novel regions. This analysis shows that using later generations of an advanced intercross greatly facilitates fine-mapping of confidence intervals, resolving three F(2)-F(3) QTL into multiple linked loci and narrowing confidence intervals of other loci, as well as allowing identification of additional QTL. Further characterization of the biological bases of these QTL will help provide a better understanding of the genetics of small variations in long-bone length.
  Mammalian Genome 04/2009; 20(4):224-35. · 2.89 Impact Factor
• Source

  Available from: Andrea Peripato

  Article: Quantitative trait loci for body size components in mice.

  Jane P Kenney-Hunt, Ty T Vaughn, L Susan Pletscher, Andrea Peripato, Eric Routman, Kilinyaa Cothran, David Durand, Elizabeth Norgard, Christy Perel, James M Cheverud
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  ABSTRACT: Do body size components, such as weights of internal organs and long bone lengths, with different functions and different developmental histories also have different genetic architectures and pleiotropic patterns? We examine murine quantitative trait loci (QTL) for necropsy weight, four long bone lengths, and four organ weights in the LG/J x SM/J intercross. Differences between trait categories were found in number of QTL, dominance, and pleiotropic patterns. Ninety-seven QTLs for individual traits were identified: 52 for long bone lengths, 30 for organ weights, and 15 for necropsy weight. Results for long bones are typically more highly significant than for organs. Organ weights were more frequently over- or underdominant than long bone lengths or necropsy weight. The single-trait QTLs map to 35 pleiotropic loci. Long bones are much more frequently affected in groups while organs tend to be affected singly or in pairs. Organs and long bones are found at the same locus in only 11 cases, 8 of which also include necropsy weight. Our results suggest mainly separate genetic modules for organ weights and long bone lengths, with a few loci that affect overall body size. Antagonistic pleiotropy, in which a locus has opposite effects on different characteristics, is uncommon.
  Mammalian Genome 07/2006; 17(6):526-37. · 2.89 Impact Factor