Research Results - (PDF, 101 mb) - USAID

not significant. This could imply that if M60
is associated with resistance to helminths, its
mediated effects are in lowering the impact
that parasites have on the goats, rather than
through a reduction in the number of worms
established in the gut.
Currently, confounding in the data is
a serious problem. When t-tests were performed
within line for each production
character, none of the previously significant
differences were found, in part, due to the
small sample sizes within lines. The differences
which were found to be significant
were most likely to have been due to chance.
The lack of an association between markers
and productivity within lines indicates that
larger numbers of animals will have to be
sampled. Some of the reasons for a lack of
differences between lines are as follows. The
markers present in relatively high frequencies
were found only within lines (or sire
groups); furthermore, breed effects and
heterosis are also contributing to the confounding
of the data. For example, line I is
primarily KDPG, while line 5 is almost
completely EAG. The variation in mature
size, by breed, may be the primary factor
controlling differences observed for growth.
Heterosis, not only in terms of growth, but in
terms of resistance to helminths may also be
a part of the reason why line and marker
differences were found.
Even though a number of problems
exist with the collected data at this time, the
initial results from this experiment are promising.
As more data on animals are collected, we
will be better able to assess the potential for
using molecular genetics techniques in conjunction
with other animal breeding practices.
However, even if markers ai3sociated with
resistance to internal parasites and productivity
are not located, the breeding project will still be
able to select for resistance based upon animal
performance, PCV and FEC.
B.RAPD Analysis
Table 8. Band scoring for APMd and AP9
One hundred and five goats were bled
and DNA was extracted. The goats were of
various breed types representing purebred Galla
and East African, first generation two-way and
four-way (KDPG) crosses and second generation
KDPG goats. Genetic polymorphisms were
detected using Randomly Amplified Polymorphic
DNA marker techniques (RAPD). This
procedure uses the polymerase chain reaction
(PCR) to randomly amplify segments of an
animal's genome which are surrounded by an
arbitrarily chosen ten base primer sequence.
After completion of the PCR, the contents are
then electrophoresed on an agarose gel to
separate DNA based on the length of the amplifled
products. Initially, five different 10 base
primers were used to screen the caprine genome
for polymorphisms. Three primers detected
polymorphic bands: AP3, AP8d, and AP9 with
three, three, and five polymorphic bands,
respectively. The results of band scoring for
AP8d and AP9 are in table 8.
Primer Number Fragment Occurrence Frequency
Scored Length (bp)
AP8d 43 1020 32 .744
920 28 .651
850 1 .023
AP9 53 915 46 .885
905 39 .750
575 1 .019
540 8 .151
500 16 .302
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