Comparative mapping and positional candidate cloning of economic trait loci on bovine chromosomes 2 and 4 /
One of the major goals of genomic research for the livestock industries is to identify economic trait loci and directly select elite animals based on their genetic components. A resource herd comprising 701 animals from Angus x Brahman F2 and backcrosses has been developed for this purpose. Initial...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=732556081&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | One of the major goals of genomic research for the livestock industries is to identify economic trait loci and directly select elite animals based on their genetic components. A resource herd comprising 701 animals from Angus x Brahman F2 and backcrosses has been developed for this purpose. Initial interval analyses found several ETLS with high LOD support (LOD>3) on bovine chromosomes 2 and 4. This dissertation is a study of the identification of ETLS controlling beef cattle growth and carcass quality using the positional candidate cloning method. Nine genes, SCP2, GDF8, GCG, NEB, TTN, IGFB2, MYLI, FN1, ACADL, and two genes, LAMBI and BPGM, were selected as candidate genes for ETLs on BTA2 and BTA4, respectively, using the human-bovine comparative map. These genes were isolated from a bovine bacterial artificial chromosome (BAC) library with 93% bovine genomic representation and an average insert size of 133 kb. All of these genes, except SCP2, were physically mapped to bovine chromosomes 2 or 4 by fluorescence in situ hybridization (FISH) using BAC DNA as probes. Either a polymorphic microsatellite or an SSCP marker was developed from the positive BAC clones containing candidate genes to integrate these genes into our genetic maps and interval mapping analyses. Radiation hybrid (RH) mapping is an efficient approach for physical mapping. Twenty-six loci, including eight selected genes and eighteen microsatellites, were used to construct a comprehensive RH map of BTA2. The orders obtained by the three mapping methods were in agreement. Interval analyses were performed by integrating all the candidate genes into the genetic maps for BTA2 and BTA4. ETL peaks with LOD scores greater than 2 were detected for seven traits on BTA2, including WWT, OAWT, OMWT, ADGOF, SWT, HCW and KPH, and for two traits on BTA4, including C18:0 and R1. A candidate gene would be tentatively identified as the ETL if it was located in the I-LOD interval containing an ETL. None of the candidate genes was in these I-LOD intervals based on the results of this study. Thus, further work will be needed in the future to identify additional candidate genes. |
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| Item Description: | Vita. "Major Subject: Genetics". |
| Physical Description: | xii, 118 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references: pages 104-117. |