Sub1A is an ethylene-response-factor-like gene that confers submergence tolerance to rice.

Most Oryza sativa cultivars die within a week of complete submergence--a major constraint to rice production in south and southeast Asia that causes annual losses of over US 1 billion dollars and affects disproportionately the poorest farmers in the world. A few cultivars, such as the O. sativa ssp. indica cultivar FR13A, are highly tolerant and survive up to two weeks of complete submergence owing to a major quantitative trait locus designated Submergence 1 (Sub1) near the centromere of chromosome 9 (refs 3, 4, 5-6). Here we describe the identification of a cluster of three genes at the Sub1 locus, encoding putative ethylene response factors. Two of these genes, Sub1B and Sub1C, are invariably present in the Sub1 region of all rice accessions analysed. In contrast, the presence of Sub1A is variable. A survey identified two alleles within those indica varieties that possess this gene: a tolerance-specific allele named Sub1A-1 and an intolerance-specific allele named Sub1A-2. Overexpression of Sub1A-1 in a submergence-intolerant O. sativa ssp. japonica conferred enhanced tolerance to the plants, downregulation of Sub1C and upregulation of Alcohol dehydrogenase 1 (Adh1), indicating that Sub1A-1 is a primary determinant of submergence tolerance. The FR13A Sub1 locus was introgressed into a widely grown Asian rice cultivar using marker-assisted selection. The new variety maintains the high yield and other agronomic properties of the recurrent parent and is tolerant to submergence. Cultivation of this variety is expected to provide protection against damaging floods and increase crop security for farmers.

The c.940G variant of the Microcephalin (MCPH1) gene is not associated with microcephaly or mental retardation.

It was reported that positive selection has acted upon a gene involved in autosomal recessive primary microcephaly, Microcephalin (MCPH1/BRIT1), located at chromosome 8p23. We tested if the reported diagnostic single nucleotide polymorphism (SNP) (G37995C or c.940G > C) of a derived haplogroup of the MCPH1 gene had significantly different frequencies in mental retardation (MR) patients and in MR patients with microcephaly as compared to MR patients without microcephaly and controls in African-American and Caucasian populations in South Carolina, US. Our results suggest that there is little or no association between the MCPH1 c.940G allele and either microcephaly or MR. However, we found highly significant racial differences in the c.940G > C SNP allele frequencies between African-American and Caucasian populations.