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FRUITFULL, also called FUL or AGL8, is an Arabidopsis thaliana developmental regulatory gene encoding a MADS-box transcription factor. In the fruit, it helps establish normal valve tissue identity. The gene, its protein product and a mutant plant's phenotype are different levels of description.

The 1998 study of the ful-1 mutant identified an inserted enhancer-trap element disrupting the gene. A reporter marked valve tissue, and mutant valve cells failed to elongate and differentiate normally.^[ref] Comparing local expression and cell anatomy supplies more mechanistic information than noting only that a mature fruit is short.

A later genetic analysis clarified that the effect need not mean that FRUITFULL directly drives every elongation step. Its regulatory role includes preventing misplaced INDEHISCENT activity.^[ref] In a causal comparison, defective growth machinery and altered tissue identity can both produce a short organ. Perturbing the regulatory pathway and measuring which identity develops helps distinguish those explanations. The combined history connects gene expression, cell differentiation, fruit dehiscence and seed dispersal without treating final organ length as a direct assay of a single molecular function.

INDEHISCENT, abbreviated IND, is an Arabidopsis thaliana regulatory gene whose encoded transcription factor helps specify the fruit tissues required for opening and seed dispersal. The gene name and its protein product are related uses of the name; an INDEHISCENT mutant is an altered organism, not a separate anatomical layer. A 2004 study identified IND and its role in patterning dispersal-related fruit cell types.^[ref]

The distinction between growth and identity is experimentally useful. The 2004 work showed that the action of FRUITFULL included preventing misplaced IND activity, rather than simply acting as a direct fruit-elongation switch.^[ref] A malformed short fruit can therefore reflect a change in tissue identity rather than failure of a generic growth process.

A 2016 study compared normal fruits with INDEHISCENT mutants and found an early defect in the cell divisions that form the dehiscence zone. It connected the factor to auxin transport and response during early development.^[ref] Together these experiments motivate a regulatory explanation: local gene expression changes developmental signals, those signals influence cell behaviour, and the resulting tissue arrangement makes a separation layer possible.

Q. Gu is the first-listed author of the 1998 study identifying the developmental role of FRUITFULL in Arabidopsis thaliana. The paper connected a disrupted MADS-box transcription factor gene with defective cell differentiation in fruit valves. Its indexed byline gives Q. Gu; an expanded given name is not established here.^[ref]

The experiment made the mutation informative in two ways. An enhancer trap insertion disrupted the gene, while its reporter gene marked expression in valve tissues. In the mutant, valve cells failed to elongate and differentiate normally; the mature fruit consequently remained short and its tissues grew without normal coordination.^[ref]

The combination is more revealing than organ length alone: a local expression pattern and a tissue-specific defect connect a regulatory gene to development at the cell level. They support a role in the process without demonstrating that every downstream growth gene is a direct transcriptional target.