mating systems Flashcards
what is the animal breeding scheme?
animal improvement and genetic change
- selection method(whos records)
- selection technique (how and what)
- mating system
what different types of mating systems are there?
within breed and across breeds
whats the difference within breeds and across breeds
within breeds - line breeding, outcrossing and random mating
across breeds - crossbreeding(grading up, synthetic production)
what is inbreeding?
it’s used in purebreds - like race horses and show dogs
it can be used in poultry to produce lines which are then crossed
mating of close relatives
why would you want to inbreed?
keep the genetics of good animals - remake champions
increase number of homozygous loci and frequency of specific populations
what is linebreeding
form of inbreeding where a prominent relative is re introduced
what needs to happen for inbreeding to work
cull heavily or be very homozygous already
what type of relative is used ?
direct - in line of descent directly - grandmother
cullateral - common ancestor - but not in a direct line (cousin)
can have both
What are the dangers of inbreeding?
exposes deleterious recessives
what is an inbreeding coefficient?
fraction of loci an individual has with 2 like alleles inherited from a common ancestor
therefore chance of homozygosity of a rare mutant allele
what affects of inbreeding are there?
must often cull due to harmful recessive (genetic defects)
loss of fertility
loss of vigor, hardness
why inbreed:
develope a new breed or line
maintain a rare breed
recreate a prized individual
develop lines for crossing
highly inbred research animals
detect recessives the breed carries
what is outcrossing?
mating animals within the same breed that are not related
what is random breeding?
draw mates at random
corral together and let them decide
why consider random mating?
to maintian gene pool
zoo animals
rare domestic breeds
