General terms:
* Traits: This is a very common synonym, often used interchangeably with "characteristics."
* Phenotype: This refers specifically to the observable characteristics of an organism, as determined by its genotype (genetic makeup) and environmental influences.
* Attributes: This is a broader term that can refer to any distinguishing feature, including those not directly related to genetics.
* Features: Similar to attributes, this word emphasizes the outward appearance or qualities of something.
More specific terms:
* Alleles: These are alternative forms of a gene, responsible for variations in traits.
* Genotype: This refers to the genetic makeup of an individual, which determines its potential for expressing certain traits.
* Phenotypic variation: This describes the range of observable traits within a population.
* Heritable traits: These are characteristics passed down from parents to offspring through genes.
Informal terms:
* Qualities: This is a less formal synonym for characteristics.
* Marks: This emphasizes distinct features that set something apart.
* Aspects: This term highlights specific parts or components of an organism's makeup.
The best synonym to use will depend on the specific context of your writing and the level of formality required.