5. Hybridization
The double strand of DNA consists of a series of set base pairs; if one strand has
a certain sequence, the corresponding sequence connected to it has been determined. It is also possible to dissociate and combine the double strand easily. To
take advantage of this property and investigate a particular DNA sequence (gene),
one simply needs to mark single-chain DNA that is already known with a
radioactive isotope, and use a probe to choose the combining part of the unknown
single DNA chain.
B. Components of Introduction
1. Inserting
Various approaches exist for introducing genes into an egg cell, including the
calcium phosphate, microinjection, cell chimera, cell fusion, and electroporation
methods. A portion of the gene introduced into the cell happens to be incorporated
into the genome, where it is replicated and distributed to cells throughout the body
with the remaining genome at the time of cell division. To date, microinjection of a
highly concentrated gene solution near the nucleus of the fertilized egg appears to
be the surest approach for introduction to the genome.
Before, it was thought that foreign genes had to be attached to a vector such as a
virus, plasmid, or transposon to increase the efficiency of introduction into the gg
genome, but such introduction also takes place effectively through the genes alone.
The use of ring-shaped rather than linear chains for the DNA fragments is also
reported to be more effective.
The success or failing of foreign gene introduction can be examined through
hybridization, with the entire DNA of the resulting fry separated and the gene or its
main sequence probes.
2. Promoting Expression
As a following step, it is important to induce actual expression of the gene that
has been introduced into the fish (host) genome. In other words, it must be transcribed to mRNA and translated into a specific protein on the ribosome so that the
host’s properties are transformed. Typically, the resulting mRNA or proteins are
examined to determine whether expression has taken place. It is also necessary to
ensure expression in the proper part (tissue) of the host body and the proper time.
Additionally, it may be possible for humans to control gene activity by inducing
expression only when a specific kind of signal (expression stimulus) has been sent
from outside. In this case, the question of how to treat the introduced gene becomes
important. Combination with a suitable promoter is essential when promoting or
controlling expression. Often, the promoter possessed by the gene itself is simply
used as it is.
4.4 Gene Manipulation
101
The double strand of DNA consists of a series of set base pairs; if one strand has
a certain sequence, the corresponding sequence connected to it has been determined. It is also possible to dissociate and combine the double strand easily. To
take advantage of this property and investigate a particular DNA sequence (gene),
one simply needs to mark single-chain DNA that is already known with a
radioactive isotope, and use a probe to choose the combining part of the unknown
single DNA chain.
B. Components of Introduction
1. Inserting
Various approaches exist for introducing genes into an egg cell, including the
calcium phosphate, microinjection, cell chimera, cell fusion, and electroporation
methods. A portion of the gene introduced into the cell happens to be incorporated
into the genome, where it is replicated and distributed to cells throughout the body
with the remaining genome at the time of cell division. To date, microinjection of a
highly concentrated gene solution near the nucleus of the fertilized egg appears to
be the surest approach for introduction to the genome.
Before, it was thought that foreign genes had to be attached to a vector such as a
virus, plasmid, or transposon to increase the efficiency of introduction into the gg
genome, but such introduction also takes place effectively through the genes alone.
The use of ring-shaped rather than linear chains for the DNA fragments is also
reported to be more effective.
The success or failing of foreign gene introduction can be examined through
hybridization, with the entire DNA of the resulting fry separated and the gene or its
main sequence probes.
2. Promoting Expression
As a following step, it is important to induce actual expression of the gene that
has been introduced into the fish (host) genome. In other words, it must be transcribed to mRNA and translated into a specific protein on the ribosome so that the
host’s properties are transformed. Typically, the resulting mRNA or proteins are
examined to determine whether expression has taken place. It is also necessary to
ensure expression in the proper part (tissue) of the host body and the proper time.
Additionally, it may be possible for humans to control gene activity by inducing
expression only when a specific kind of signal (expression stimulus) has been sent
from outside. In this case, the question of how to treat the introduced gene becomes
important. Combination with a suitable promoter is essential when promoting or
controlling expression. Often, the promoter possessed by the gene itself is simply
used as it is.
4.4 Gene Manipulation
101