animal breeding and genetics Flashcards
domestication
process of adapting wild plants and animals to live in association with humans
when did live stock domestication start
~10,000 years ago
animal domestication and production requirements
-feeding (nutrition)
-animal health
-selection of stock (breeding and genetics)
in the beginning what kind of traits were selected for
-observable ones (phenotype)
-color, size, speed, etc
selective breeding
-improve growth, performance, ect
preventative medicine
-cull decisions (cull doesnt always mean kill)
-few genetic diseases are treatable
individuals vs herd
-individual- can be culled and change herd influence
-herd- influence made by mating systems, selection methods, selection techniques
what are the majority of clients seeking genetic advice
purebred breeders
what is the primary product of purebred producers
-genes
-bull, bohr, semen, embryo
=/
congenital (present at birth)
=
inherited (not present at birth, have but shows later, huntingtons disease)
~
familial (cancer or diabeties, may be present but lifestyle can impact)
what are the different kinds of patterns of inheritance
-single gene
-chromosomal
-multifactorial
-teratogenic
single gene inheritance
There are five basic modes of inheritance for single-gene diseases: autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, and mitochondrial
chromosomal gene inheritance
inherit large chunks of DNA
multifactorial gene inheritance
complex genetics plus environment (diabetes)
teratogenic inheritance
usually caused by agent or toxin
what is the importance of family history
gives more power to find cause of trait
what are some helpful things to know for a family tree
-age of parents
-number of previous offspring (normal and abnormal)
-sex of affecteds
-number of miscarriages and still births
-breed
triangle pedigree symbol
sex unspecified or ambiguous
solid black dot or square family tree symbol
female affected or male affected
cross through family tree symbol
dead
circle with small black dot in it family tree symbol
carrier of X-linked
half black half white circle family tree symbol
heterozygous female carrier (one allele affected one normal)
autosomal single gene inheritance
-on non sex chromosome
-dominant and recessive
-if dominant is present its always expressed
-need two copies of recessive to produce phenotype
sex linked single gene inheritance
-X and Y in mammals, Z and W in birds
-dominant
-recessive
what are the heterogenemic sex in birds and mammals
birds=female
mammals=male
autosomal dominant generalizations
-most non-enzyme protein disorders
-veritable expressivity (degree)(light dimmer)
-reduced or incomplete penetrance (present or absent)(light switch)
-many are the result of a new mutation
-homozygote is often lethal
variable expressivity (degree) example
-manx cat
-show quality “ideal” manx are tailless
-but some are missing only some tail vertebrae
-genotype: Mm
-belt in galloway cattle
-dominant allele for presence of belt
-variable expression
reduced penetrance (present or absent)
-full
-all individuals with the allele express the phenotype
-reduced
-not all individuals show phenotype
-i.e. 70% penetrance=70% with the allele express the phenotype
reduced penetrance canine gallbladder mucoceles
-dominant but doesn’t always show
-dominant with reduced penetrance
-rare disease that affects certain dog breeds (sheltie, cairn terrier, Pomeranian, etc)
autosomal dominant generalization example
-many are the result of a new mutation
-polled in cattle- more than one polled mutation
-80kb duplication in holstein-friesian cattle
-202 bp insertion/deletion (indel) in beef breeds
-homozygote is often lethal
-manx cat, mexican hairless, overo horse, camarillo white horse
