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Fig. 3 | Genome Biology

Fig. 3

From: Large-scale genomic and transcriptomic profiles of rice hybrids reveal a core mechanism underlying heterosis

Fig. 3

The diagram of Hill reactions illustrates the model of homo-insufficiency under insufficient background (HoIIB). a The simulated dominant degree of the target site under the activator background with different sufficiencies (X/K) and different μ1 with null allele and one functional allele under one regulator background. b The simulated dominant degree of the target site with same homologous backgrounds, but the two alleles in F1 are regulated by different factors in the background for positive regulation. c The simulated dominant degree of the target site with the same positive regulators or responsors as the background when allele 1 showing larger maximum function and higher affinity and allele 2 showing smaller maximum function and lower affinity (μ1 > μ2 and K1 / K2=1/5). d The simulated dominant degree of the target site with the same positive regulators or responsors as the background when allele 1 showing larger maximum function but lower affinity and allele 2 showing smaller maximum function but higher affinity (μ1 > μ2 and K1 / K2=5/1). e The red notched ellipse represents the target factor, and that with black star * indicates the target factor whom is activated by its activators (as the background of the target factor), which are represented by the blue diamonds. Here, we assume that one allele of genotype A can be bonded and activated by at least two units of activators, but the allele of genotype a is loss-function and cannot be bonded by the activator, and the activators can be randomly attached by each of two alleles in homozygote AA. The dotted blank diamonds are the required units of activators to activate all two alleles of AA in parent 1 (P1). The target factor will show overdominance (OD), where the production of heterozygote (orange line, F1) is higher than that of P1 (red line), when the quantity of activator is too insufficient to activate even one allele of P1 but can activate the allele A in F1 in most cases; and the target factor will show (partial-) dominance (D), where the production of heterozygote is higher than the middle-parent (grey dotted line), when the quantity of activator is relatively insufficient to activate all two alleles of P1 but can activate the allele A in F1 in most cases; and when the quantity of activator is sufficient to activate all two alleles of P1, the target factor will show additive effect, where the production of F1 is similar to or equal to middle-parent (almost overlap between dotted grey line and orange line); so the dominance degree (d/a) of target factor (purple line) will decrease along with the increase of activator (i.e., from insufficient to sufficient). The parameters used here are μ=1, n=2, and K = 1

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