Re: What can be used as a host cell during cloning, besides bacteria and yeast?

Cloning, in terms of standard laboratory research, is a means to amplify or
express desired genes.  In theory, almost any cell capable of DNA
replication could be used as a host (e.g. red blood cells do not have a
nucleus or DNA and would not have the appropriate machinery to deal with
introduced DNA).  However, in practice, only certain cell types can be
manipulated in the lab for cloning.  A host cell is suitable if you can
propagate it, have some mechanism by which to insert the DNA, and have some
means of seeing the result of your cloning (if you’re expressing) or some
means of re-extracting your DNA (if you’re amplifying).

That said, bacteria and yeast are the most common host cells for their ease
of growth and manipulation.  Mammalian cells are also regularly used,
especially in medically-related research or for expression of genes that
require processing unique to mammals.  The most common mammalian cell lines
are of human, mouse or monkey origin; however, many other animal or cell
types are used.  Less common, but also well-known, are insect cells as
cloning hosts.

A little more specialized is the cloning into a cell of a whole organism. 
C. elegans (a type of roundworm) is often used, especially in aspects of
cell biology research such as development.  Procedures for cloning into
plant cells are also well-established and have great implications in
genetically modified crop research.  Also used are mice and fish (e.g.
zebrafish).

I should note that cloning into whole organisms is not the same thing as
the cloning of a whole animal.  Here, I refer to the common practice of
introducing a gene or genes into cells of a host organism for a number of
different possible purposes (e.g., research in developmental biology,
cancer research, etc.).  Cloning of a whole organism (such as Dolly)
requires the transfer of a whole genome into an emptied cell, and is still
a very error-prone process.