ANSC 313 Lecture 3: genetics inbreeding
LECTURE 7!
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why inbreeding?!
develop "new" breed or line!•
mutant color!◦
maintain rare breed!•
i.e no alternative!◦
zoo animals!◦
recreate a prized individual!•
line breeding!◦
race horses!◦
develop lines for crossing!•
company broiler chicken!◦
highly inbred research animals!•
lab mice strains!◦
detect recessives the breed carriers!•
cull to "clean up"!◦
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heterosis!
monoallelic gene expression: related to immunity!•
wide range of genes that are monoallelic, i.e. each neutron receptor expresses only one ◦
allele!
immunoglobins!◦
T cell receptors!◦
interleukins!◦
natural killer cells!◦
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Crossbreeding!
mating animals of 2 different breeds!•
especially improves traits of "low" heritability!•
fertility!◦
hardiness/ stamina!◦
but also growth is improved ( is trait of high heritability)!•
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genetic principles involved in crossbreeding!
heterosis!•
new combinations of genes works better!◦
i.e. heterozygotes superior!◦
complementarity!•
mates "match" or "compensate"!◦
does not work if you don't match mates well!◦
i.e. good mother X large bull!◦
to bring in good traits of mother and bull!‣
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heterosis = " hybrid vigor"!
only meant to occur when trait has non-additive gene action!•
therefore greastedt effects on traits of "low" heritability!•
negligible effects on traits of high heritability !•
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