Fig. 2.

Map-based isolation of the cotton hybrid lethality gene Le₄. (A) Le₄ was mapped on the D11 chromosome between the markers BNL3279 and BNL1154 using an F₂ population. The genetic distance between the markers was 9.4 cM. Le₄ was further fine-mapped to a region between markers W8424 and K1805 using 734 dominant individuals. A 267-kb region containing three putative ORFs was obtained by mapping this region with sequences from G. hirsutum TM-1. (B) Transcriptome analysis was used to compare the expression levels of Le₄ in leaves from lethal F₁ and normal F₁ plants at four different developmental stages (S1–S4). Data are means of two or three replicates. (C) qRT-PCR analysis was used to compare the transcript levels of Le₄ in leaves from lethal F₁ and normal F₁ plants at four different developmental stages. Data are means (±SE) of three replicates. Significant differences between means were determined using Student’s t-test: **P<0.01.