Encyclopedia of Biology

insertion reaction Achemical reaction or transfor-
mation of the general type X–Z + Y Ô X–Y–Z in
which the connecting atom or group Y replaces the
bond joining the parts X and Z of the reactant XZ.

insertion sequence A shortstretch of mobile bacte-
rial DNA known as a transposon that has the capacity
to move between different points within a genome, or
change positions; special sequences at their terminal
ends allow them to integrate into strands of DNA; usu-
ally are inverted repeats (two copies of the same or
related sequence of DNA repeated in opposite orienta-
tion on the same molecule) at the ends of the insertion
sequence; can alter gene expression; involved in trans-
position.

insight learning Having the ability to perform the
appropriate or correct behavior response in a first-time
experience on the first try.

instinct An organism’s innate, or inborn, intuitive
ability to respond to a given stimulus in a fixed way.

instinct 177

This insect (Phasmatodea) from the Bahamas is a good example of cryptic coloration and mimicry.(Courtesy of Tim McCabe)

A type of chromosomal abnormality in which a DNA sequence is

inserted into a gene, disrupting the normal structure and function

of that gene.(Courtesy of Darryl Leja, NHGRI, National Institutes

of Health)

area

being

inserted inserted

area

Before insertion After insertion

chromosome

4

chromosome

4

chromosome

20

chromosome

20