The Gm-Pi linkage heterogeneity in view of Pi M subtypes |
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| Authors: | T GEDDE-DAHL JR R R FRANTS† B OLAISEN† A W ERIKSSON† E VAN LOGHEM§ L LAMM¶ |
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| Institution: | *Genetics Laboratory, NorskHydro's Institute for Cancer Research, Oslo;†Institute of Human Genetics, Free University, Amsterdam;†Institute of Forensic Medicine, University of Oslo, Oslo;§Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam;¶Blood Bank and Tissue Typing Laboratory, University Hospital, Aarhus |
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| Abstract: | In this study linkage between the loci for Gm (γ-type heavy-chain immunoglobulin markers) and Pi (α1-antitrypsin/α1-protease inhibitor) has been shown in families segregating for the Pi M subtypes (Ml, M2, M3 and Msal) as identified by separator isoelectric focusing. The estimate for the Gm-Pi (M-type) recombination is 0-29 (95% limits 0-24-O37) at a peak lod score of 4-31 and with no sex difference. This value is not significantly different from updated recombination frequency estimates for Gm-Pi in Pi MS (0-26) and Pi MZ, SZ and FZ families (0 21). The overall Gm-Pi recombination fraction estimate of 0 26 (95 % limits O23-0-30) at a peak lod score of 20-75 must now be considered as solid. There is a significant heterogeneity within the male Pi MZ families in that the new Finnish families show a higher recombination between Gm and Pi. There is also a possible segregation distortion (Z:M = 23:8). The heterogeneity is discussed in terms of haplotypes, the behaviour of which could be determined by linked genes or chromosomal rearrangements. The possibility that the α1-antitrypsin level influences recombination frequency has not been ruled out, but cannot explain the heterogeneity within Pi MZ families. |
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