Morphotype
Definition
A phytolith shape class defined by the geometry of the silica body: bilobate, cross-shaped, saddle-shaped, elongate, dendritic, and so on. Individual morphotypes are assigned to grass subfamilies and used to reconstruct the vegetation community represented in a soil or sediment sample.
- Biological domains
- Applies to both bacteria (colony variants) and plants (silica body shapes)
- Origin mechanism
- In bacteria, arises from spontaneous mutations in a culture; in plants, refers to a shape class defined by the geometry of the silica body
- Forensic value
- Creates signatures in microbial cases and enables vegetation reconstruction in archaeological and environmental samples
Common questions
What is a morphotype and why does it matter in forensics?+
A morphotype is a visually distinct variant that arises from a spontaneous mutation in a bacterial culture, or a specific shape class in plant silica bodies. In microbial forensics, the presence of multiple morphotypes in a bacterial sample can create a unique signature that links it to a particular source. In plant forensics, different morphotypes help researchers identify which grasses were present in a soil or sediment sample.
How are morphotypes used in bacterial forensics?+
In the Amerithrax case, four morphotypes of Bacillus anthracis were identified in the same preparation, and their co-presence served as a forensic signature that could be linked to a specific flask. This demonstrates how the pattern of bacterial variants within a sample can help trace its origin.
What are the main morphotypes used in phytolith analysis?+
Phytoliths are classified by their silica body shapes, including bilobate, cross-shaped, saddle-shaped, elongate, and dendritic forms. Each morphotype is assigned to specific grass subfamilies, allowing investigators to reconstruct past vegetation communities from soil and sediment samples.
Related terms
- Caryopsis
- The grain of a grass: a single-seeded fruit in which the seed coat is fused to the ovary wall. Shape, size, and...
- Floret
- The basic reproductive unit of a grass spikelet, consisting of the lemma, palea, and the enclosed flower. Floret morphology, including lemma surface,...
- Lemma
- The lower of the two bracts enclosing the grass floret. Its surface texture, venation, awn character, and marginal features are major identification...
- Microbial Forensics
- The application of molecular biology, genomics, and population genetics to attribution questions in cases involving microorganisms, toxins, or biological agents used in...
- Multi-Locus Sequence Typing (MLST)
- Species-level and strain-level characterisation using DNA sequences from five to seven conserved housekeeping genes. Provides higher resolution than 16S rRNA alone and...
- NBFAC
- National Bioforensic Analysis Center, Fort Detrick, Maryland. Established 2004 as the US federal government's primary bioforensics reference laboratory for biological evidence in...
- Phylogenetic Proximity
- The principle in viral forensics that transmission between individuals is supported when their viral sequences cluster together in a phylogenetic tree separately...
- Phytolith
- Opaline silica body precipitated in or between plant cells during growth. Grass phytoliths are produced in high quantities and persist in soil...
- RMR-1029
- The reference material repository flask at USAMRIID Fort Detrick that was identified as the probable source material for the 2001 anthrax letters,...
- Select Agent
- A biological agent or toxin designated by the US Centers for Disease Control and Prevention and USDA as posing a severe public...
- Subfamilies Panicoideae and Chloridoideae
- Two of the major grass subfamilies. Panicoideae (warm-season C4 grasses of humid tropics and subtropics) are characterised by bilobate and cross-shaped phytoliths....
Explained in these topics
- Grass and Grass Phytolith AnalysisA phytolith shape class defined by the geometry of the silica body: bilobate, cross-shaped, saddle-shaped, elongate, dendritic, and so on. Individual morphotyp...
- Microbial Forensics: Anthrax Letters and Biothreat AttributionA visually distinct colony variant arising from a spontaneous mutation in a bacterial culture. In the Amerithrax case, four morphotypes of Bacillus anthracis A...