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Genetic Mapping of Thermotolerance Differences Between Species of Saccharomyces Yeast via Genome-Wide Reciprocal Hemizygosity Analysis
Published on: August 12, 2019
Maize HapMap2 identifies extant variation from a genome in flux.
Jer-Ming Chia1, Chi Song, Peter J Bradbury
1Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.
Nature Genetics
|June 5, 2012
Summary
Researchers identified 55 million SNPs in maize and its wild relative, Tripsacum, revealing extensive structural variations. This genetic diversity offers potential for integrating beneficial traits like drought tolerance into cultivated maize.
Area of Science:
- Genomics
- Plant Genetics
- Evolutionary Biology
Background:
- Maize (Zea mays) breeding has focused on yield, underutilizing genetic diversity from undomesticated varieties.
- Characterizing the vast genetic variation in maize has been historically challenging.
Purpose of the Study:
- To identify and characterize genetic variations, including structural variations, in a diverse set of maize and Tripsacum lines.
- To investigate the genetic basis of genome size variation within Zea mays and between maize and Tripsacum.
Main Methods:
- Employed a population genetics scoring model to analyze genetic variation across 103 lines.
- Identified millions of single nucleotide polymorphisms (SNPs) and characterized structural variations.
- Investigated genome size variation drivers, distinguishing transposable elements from allopolyploidy and chromosomal knobs.
Main Results:
- Discovered 55 million SNPs across pre-domestication and domesticated Zea mays, plus a Tripsacum relative.
- Found pervasive structural variations in the maize genome, enriched at trait-associated loci.
- Determined Tripsacum's larger genome is due to transposable elements, while maize genome size variation relates to chromosomal knobs.
- Observed significant overlap in gene content between maize and Tripsacum.
Conclusions:
- The extensive genetic variation and structural diversity in maize and Tripsacum provide a resource for crop improvement.
- Adaptations present in Tripsacum, such as perennialism and stress tolerance, could potentially be integrated into maize through genetic introgression.
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