Severe hypertension caused by alleles from normotensive Lewis for a quantitative trait locus on chromosome 2

2005 ◽  
Vol 22 (1) ◽  
pp. 70-75 ◽  
Author(s):  
Vasiliki Eliopoulos ◽  
Julie Dutil ◽  
Yishu Deng ◽  
Myrian Grondin ◽  
Alan Y. Deng
Keyword(s):  
Quantitative Trait Locus ◽  
Quantitative Trait ◽  
Congenic Strain ◽  
Severe Hypertension ◽  
Chromosome 2 ◽  
Paradoxical Effect ◽  
Angiotensin Ii Receptor ◽  
Animal System ◽  
Trait Locus ◽  
Normotensive Strain

Pursuing fully a suggestion from linkage analysis that there might be a quantitative trait locus (QTL) for blood pressure (BP) in a chromosome (Chr) 2 region of the Dahl salt-sensitive rat (DSS), four congenic strains were made by replacing various fragments of DSS Chr 2 with those of Lewis (LEW). Consequently, a BP QTL was localized to a segment of around 3 cM or near 3 Mb on Chr 2 by comparative congenics. The BP-augmenting alleles of this QTL originated from the LEW rat, a normotensive strain compared with DSS. The dissection of a QTL with such a paradoxical effect illustrated the power of congenics in unearthing a gene hidden in the context of the whole animal system, presumably by interactions with other genes. The locus for the angiotensin II receptor AT-1B ( Agtr1b) is not supported as a candidate gene for the QTL because a congenic strain harboring it did not have an effect on BP. There are ∼19 known and unknown genes present in the QTL interval. Among them, no standout candidate genes are reputed to affect BP. Thus the QTL will likely represent a novel gene for BP regulation.

Complete and overlapping congenics proving the existence of a quantitative trait locus for blood pressure on Dahl rat chromosome 17

2005 ◽  
Vol 21 (1) ◽  
pp. 112-116 ◽  
Author(s):  
Myrian Grondin ◽  
Vasiliki Eliopoulos ◽  
Raphaelle Lambert ◽  
Yishu Deng ◽  
Anita Ariyarajah ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Quantitative Trait Locus ◽  
Quantitative Trait ◽  
Congenic Strain ◽  
Chromosome 17 ◽  
Congenic Strains ◽  
Genome Wide ◽  
A Genome ◽  
Trait Locus ◽  
Negative Controls

Linkage studies suggested that a quantitative trait locus (QTL) for blood pressure (BP) was present in a region on chromosome 17 (Chr 17) of Dahl salt-sensitive (DSS) rats. A subsequent congenic strain targeting this QTL, however, could not confirm it. These conflicting results called into question the validity of localization of a QTL by linkage followed by the use of a congenic strain made with an incomplete chromosome coverage. To resolve this issue, we constructed five new congenic strains, designated C17S.L1 to C17S.L5, that completely spanned the ±2 LOD confidence interval supposedly containing the QTL. Each congenic strain was made by replacing a segment of the DSS rat by that of the normotensive Lewis (LEW) rat. The only section to be LL homozygous is the region on Chr 17 specified in a congenic strain, as evidenced by a total genome scan. The results showed that BPs of C17S.L1 and C17S.L2 were lower ( P < 0.04) than that of DSS rats. In contrast, BPs of C17S.L3, C17S.L4, and C17S.L5 were not different ( P > 0.6) from that of DSS rats. Consequently, a BP QTL must be located in an interval of ∼15 cM shared between C17S.L1 and C17S.L2 and unique to them both, as opposed to C17S.L3, C17S.L4, and C17S.L5. The present study illustrates the importance of thorough chromosome coverage, the necessity for a genome-wide screening, and the use of “negative” controls in physically mapping a QTL by congenic strains.

Two closely linked interactive blood pressure QTL on rat chromosome 5 defined using congenic Dahl rats

2002 ◽  
Vol 8 (2) ◽  
pp. 81-86 ◽  
Author(s):  
Michael R. Garrett ◽  
John P. Rapp
Keyword(s):  
Blood Pressure ◽  
Quantitative Trait Locus ◽  
Quantitative Trait ◽  
Congenic Strain ◽  
Major Effect ◽  
Large Region ◽  
Chromosome 5 ◽  
Low Blood Pressure ◽  
Trait Locus

Previously we reported the construction of a congenic strain, S.LEW( 5 ), spanning a large region of rat chromosome 5. The Lewis (LEW) strain was the donor, and the Dahl salt-sensitive (S) strain was the recipient. The congenic strain included a blood pressure quantitative trait locus (QTL). In the present work, a series of nine congenic substrains were constructed from S.LEW( 5 ) which defined two closely linked blood pressure QTL in the region previously thought to contain only one. LEW low-blood-pressure alleles at both QTL were required for a major effect on blood pressure. Neither LEW allele alone had a significant effect on blood pressure. The two QTL were localized to regions 6.3 and 4.6 cM, and these were 1.0 cM apart.

A major quantitative trait locus determining serum leptin levels and fat mass is located on human chromosome 2

1997 ◽  
Vol 15 (3) ◽  
pp. 273-276 ◽  
Author(s):  
Anthony G. Comuzzie ◽  
James E. Hixson ◽  
Laura Almasy ◽  
Braxton D. Mitchell ◽  
Michael C. Mahaney ◽  
...  
Keyword(s):  
Quantitative Trait Locus ◽  
Human Chromosome ◽  
Fat Mass ◽  
Quantitative Trait ◽  
Major Quantitative Trait Locus ◽  
Chromosome 2 ◽  
Serum Leptin ◽  
Trait Locus

Quantitative trait locus analysis of multiple agronomic traits in the model legume Lotus japonicus

Genome ◽  
2007 ◽  
Vol 50 (7) ◽  
pp. 627-637 ◽  
Author(s):  
Takahiro Gondo ◽  
Shusei Sato ◽  
Kenji Okumura ◽  
Satoshi Tabata ◽  
Ryo Akashi ◽  
...  
Keyword(s):  
Quantitative Trait Locus ◽  
Quantitative Trait ◽  
Agronomic Traits ◽  
Recombinant Inbred Lines ◽  
Lotus Japonicus ◽  
Seed Mass ◽  
Chromosome 2 ◽  
Seed Traits ◽  
Model Legume ◽  
Trait Locus

The first quantitative trait locus (QTL) analysis of multiple agronomic traits in the model legume Lotus japonicus was performed with a population of recombinant inbred lines derived from Miyakojima MG-20 × Gifu B-129. Thirteen agronomic traits were evaluated in 2004 and 2005: traits of vegetative parts (plant height, stem thickness, leaf length, leaf width, plant regrowth, plant shape, and stem color), flowering traits (flowering time and degree), and pod and seed traits (pod length, pod width, seeds per pod, and seed mass). A total of 40 QTLs were detected that explained 5%–69% of total variation. The QTL that explained the most variation was that for stem color, which was detected in the same region of chromosome 2 in both years. Some QTLs were colocated, especially those for pod and seed traits. Seed mass QTLs were located at 5 locations that mapped to the corresponding genomic positions of equivalent QTLs in soybean, pea, chickpea, and mung bean. This study provides fundamental information for breeding of agronomically important legume crops.

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