Vestigiality describes homologous

Homology (biology)

Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

 characters of organism

Organism

In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

s that have seemingly lost all or most of their original function

Function (biology)

A function is part of an answer to a question about why some object or process occurred in a system that evolved through a process of selection. Thus, function refers forward from the object or process, along some chain of causation, to the goal or success...

 in a species through evolution

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

. These may take various forms such as anatomical

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

 structures, behavior

Behavior

Behavior or behaviour refers to the actions and mannerisms made by organisms, systems, or artificial entities in conjunction with its environment, which includes the other systems or organisms around as well as the physical environment...

s and biochemical pathways. Some of these disappear early in embryonic development, but others are retained in adulthood. Although the term serves a purpose in many gross phenotypic characteristics, vestigial has probably little applicability to DNA sequences, be they genes or non-coding sequences.