Quantitative trait loci mapping of genomic imprinting effects in Bos taurus x Bos indicus cattle /
An Angus x Brahman crossbred cattle population and a sex average genetic map spanning 2645 cM or 95% of the bovine genome were used to study the molecular basis for reciprocal differences in birth weight (BWT) weaning weight (WWT), hot carcass weight (HCW)) and gestation length (GEST) according to a...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=728408511&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | An Angus x Brahman crossbred cattle population and a sex average genetic map spanning 2645 cM or 95% of the bovine genome were used to study the molecular basis for reciprocal differences in birth weight (BWT) weaning weight (WWT), hot carcass weight (HCW)) and gestation length (GEST) according to a genomic imprinting model. Interval mapping using a line cross regression model modified to separate the contribution of parent-specific effects was performed. Results showed a maternally expressed quantitative trait locus (QTL) effect for BWT on Bta3, one paternally expressed and one maternally expressed QTLs on Bta5. There were two maternally expressed QTLs for WWT on Bta5 and Bta29. For HCW, there were six paternally expressed QTLs on chromosomes 3, 4, 12, 20, 23 and 28 along with further evidence for additional paternally expressed QTL peaks on both Bta4 and 12. Two maternally expressed QTLs on Bta11 and 16 influenced gestation length. All detected QTLs were significant at the genome-wise level (P < 0.0 1) with r-square values ranging from 1.66% to 9.3%. Based on the direction (sign) of the estimated QTL effects, observed reciprocal effects in the Angleton families appear to correlate with imprinting in calves produced within reciprocal crosses of Angus (Brahman) mated to F₁ parents. Increased power for imprinting analysis in this population would require a random QTL model, which does not assume fixation of alternate QTL alleles, in combination with separate QTL relationship matrices for the paternally and maternally inherited markers to estimate variance components by REML. Although no genes have yet been shown to be imprinted in cattle, even for the few that have been mapped; the putative conservation of imprinting on chromosomes 2, 4, 11, 12 and 29 was supported by correspondence to imprinted homologues in human and mouse. Specific regional delineation was compromised by poor comparative information between these genomes with respect to imprinted regions. |
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| Item Description: | Vita. "Major Subject: Animal Science". |
| Physical Description: | xii, 118 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 92-115). |