Identifying the genes underlying genetically complex traits is of fundamental importance for medicine, agriculture, and evolutionary biology. However, the level of resolution offered by traditional quantitative trait locus (QTL) mapping is usually coarse. We analyze here a trait closely related to fitness, ovariole number. Our initial interspecific mapping between Drosophila sechellia (8 ovarioles/ovary) and D. simulans (15 ovarioles/ovary) identified a major QTL on chromosome 3 and a minor QTL on chromosome 2. To refine the position of the major QTL, we selected 1038 additional recombinants in the region of interest using flanking morphological markers (selective phenotyping). This effort generated approximately one recombination event per gene and increased the mapping resolution by approximately seven times. Our study thus shows that using visible markers to select for recombinants can efficiently increase the resolution of QTL mapping. We resolved the major QTL into two epistatic QTL, QTL3a and QTL3b. QTL3a shows sign epistasis: it has opposite effects in two different genetic backgrounds, the presence vs. the absence of the QTL3b D. sechellia allele. This property of QTL3a allows us to reconstruct the probable order of fixation of the QTL alleles during evolution.
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http://dx.doi.org/10.1534/genetics.105.054098 | DOI Listing |
BMC Plant Biol
January 2025
Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.
Background: Toxic heavy metal elements in soils are major global environmental issues and easily migrate to crop grains to cause severe problems in human health, whereas moderately essential elements such as selenium are beneficial for human health. The accumulation of heavy metals and essential elements in rice grains and their genetic mechanisms are still poorly understood.
Results: We conducted genetic dissection of four toxic heavy metal elements (lead, cadmium, mercury, and chromium), one quasi metallic element (arsenic), and one essential element (selenium) in grains of 290 Xian and 308 Geng rice accessions through a genome-wide association study (GWAS) based on three statistical models and assays of element concentrations from three environments.
Rice (N Y)
January 2025
State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Rice is highly sensitive to low temperatures, making cold stress a significant factor limiting its growth, especially during the bud bursting stage. To address this, an RIL population derived from a cross between cold-tolerant and cold-sensitive rice varieties was used to identify nine QTLs linked to cold tolerance under temperatures of 4 ℃, 5 °C, and 6 ℃ using a high-density genetic map. One candidate gene, LOC_Os07g44410, was identified through gene function annotation, haplotype analysis, and qRT-PCR, with two main haplotypes (Hap1 and Hap2) showing distinct phenotypic differences.
View Article and Find Full Text PDFPlant Biotechnol J
January 2025
Department of Plant Breeding and Biotechnology, Centro IFAPA de Málaga, Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), Málaga, Spain.
Carotenoids are a diverse group of pigments imparting red, orange, and yellow hues to many horticultural plants, also enhancing their nutritional properties and health benefits. In strawberry, the genetic and molecular mechanisms regulating the natural variation of fruit carotenoid composition remain largely unexplored. In this study, we use a population segregating in yellow/white flesh to detect a major quantitative trait locus (QTL), qYellow Flesh-4B, located on chromosome 4B and accounting for 82% of total phenotypic variation.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Frontiers Science Center for Molecular Design Breeding, Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.
Rice is highly sensitive to cold stress, particularly at the booting stage, which significantly threatens rice production. In this study, we cloned a gene, CTB6, encoding a lipid transfer protein involved in cold tolerance at the booting stage in rice, based on our previous fine-mapped quantitative trait locus (QTL) qCTB10-2. CTB6 is mainly expressed in the tapetum and young microspores of the anther.
View Article and Find Full Text PDFPlant Biotechnol J
January 2025
Key Laboratory of Soybean Biology of Ministry of Education China, Key Laboratory of Soybean Biology and Breeding (Genetics) of Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, China.
Soybean cyst nematode (SCN, Heterodera glycines) is a major pathogen harmful to soybean all over the world, causing huge yield loss every year. Soybean resistance to SCN is a complex quantitative trait controlled by a small number of major genes (rhg1 and Rhg4) and multiple micro-effect genes. Therefore, the continuous identification of new resistant lines and genes is needed for the sustainable development of global soybean production.
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