90
JOHN E. OUSHINQ
specific on each cell. Multiple links of this sort join many cells into
visible aggregates termed agglutinates that strongly resist disruption
when shaken.
Antibody molecules with three combining sites do not occur, but
antiserums can contain blocking antibodies (sometimes called univalent
antibodies) which combine with erythrocytes without agglutinating
them. These behave as if they had a single combining site (although
alternative explanations can be given), combining with one blood
factor only and so blocking the combination of divalent antibody.
Special methods are available for the demonstration of blocking
antibodies.
There is always a possibility that a useful reagent cannot be replaced
when it is used up. This is a matter of concern, and efforts are continually being made to conmrve reagents and to replace them with
antibodies of comparable specificities.
The agglutination reaction, in various forms, has been used almost
exclusively in marine research as it is simple, yet sensitive. The
reader should consult the general references for other kinds of tests
for antibody that are ayailable.
D. Genetic considerations of blood group phenotypes
The analysis of blood group data on marine forms is generally
concerned with the following problems. First, and most fundamentally,
whether or not two samples have been drawn from the same or different
populations with respect to the phenotype frequencies of their blood
groups. Second, whether or not the blood group phenotype8 observed
are due to varying combinations of genes at the same or at different
loci. Third, whether or not the antigens involved are in Hardy-Weinberg equilibrium. Such equilibrium occurs in populations of individuals
that mate at random, are isolated from other populations, and are not
subject to disturbing selection and mutation pressures or to the effects
of genetic drift with respect to the genes determining the antigens
involved. Simple genetic theory shows that under such conditiom
allelic genes will occur in predictable frequencies with reference to
one another. The demonstration of such expected frequencies provides
strong evidence that the correct interpretation of the relations of the
genes under study haa been arrived at, and that the population from
which the sample was drawn is a single homogeneous breeding stock.
Separate breeding stocks (isolates) within a species Sometimes can be
identified where the same genes are shown to be in Hardy-Weinberg
equilibria at frequencies that differ among the stocks concerned.
Failure to demonstrate thet a genetic system is in Hady-Wehberg
JOHN E. OUSHINQ
specific on each cell. Multiple links of this sort join many cells into
visible aggregates termed agglutinates that strongly resist disruption
when shaken.
Antibody molecules with three combining sites do not occur, but
antiserums can contain blocking antibodies (sometimes called univalent
antibodies) which combine with erythrocytes without agglutinating
them. These behave as if they had a single combining site (although
alternative explanations can be given), combining with one blood
factor only and so blocking the combination of divalent antibody.
Special methods are available for the demonstration of blocking
antibodies.
There is always a possibility that a useful reagent cannot be replaced
when it is used up. This is a matter of concern, and efforts are continually being made to conmrve reagents and to replace them with
antibodies of comparable specificities.
The agglutination reaction, in various forms, has been used almost
exclusively in marine research as it is simple, yet sensitive. The
reader should consult the general references for other kinds of tests
for antibody that are ayailable.
D. Genetic considerations of blood group phenotypes
The analysis of blood group data on marine forms is generally
concerned with the following problems. First, and most fundamentally,
whether or not two samples have been drawn from the same or different
populations with respect to the phenotype frequencies of their blood
groups. Second, whether or not the blood group phenotype8 observed
are due to varying combinations of genes at the same or at different
loci. Third, whether or not the antigens involved are in Hardy-Weinberg equilibrium. Such equilibrium occurs in populations of individuals
that mate at random, are isolated from other populations, and are not
subject to disturbing selection and mutation pressures or to the effects
of genetic drift with respect to the genes determining the antigens
involved. Simple genetic theory shows that under such conditiom
allelic genes will occur in predictable frequencies with reference to
one another. The demonstration of such expected frequencies provides
strong evidence that the correct interpretation of the relations of the
genes under study haa been arrived at, and that the population from
which the sample was drawn is a single homogeneous breeding stock.
Separate breeding stocks (isolates) within a species Sometimes can be
identified where the same genes are shown to be in Hardy-Weinberg
equilibria at frequencies that differ among the stocks concerned.
Failure to demonstrate thet a genetic system is in Hady-Wehberg