ANSC 313 Lecture Notes - Lecture 13: Hereford (Cattle), Neural Tube, Congenital Heart Defect
Inheritance patterns!
single!•
chromosomal!•
multifactorial!•
teratogenic!•
!
multifactorial disorders!
many (>3) genes + environmental triggers!•
accounts for the vast majority of late onset inherited diseases !◦
sporadic occurrence in pedigree ( because you need so many genes and a trigger coming ◦
together)!
incidence not equal ( between the sexes often)!◦
difficult to eradicate!◦
!
"quantitative or complex!
many genes + environmental trigger!•
genetics + environmental!•
predisposition trigger!•
!
examples:!
cancer!•
diabetes!•
cleft plate!•
heart defects ( common in sheep)!•
!
example: cancer!
canine malignant lymphoma!•
trigger: !◦
2,4-D Herbicide ( weed & Feed)!‣
exposure 3-5 days after !◦
application via grooming!◦
cancer eye in hereford cattle!•
trigger:!◦
sunlight!‣
lack of pigment around the eye ( white faces)!‣
progresses very fast!‣
!
biological threshold!
developmental processes occur on a fixed schedule!•
at a fixed period in gestation!•
disruptions or delays cause that organ to be incompletely developed!•
that particular organ may not completely develop in the time the body gives it to develop!◦
%example: closure of neural tube: some time they are not completely closed!
time period where most humans could close there tub by a certain amount of days ‣
and if it doesn't finish at the end of the days it results in problems !
!
diabetes in dogs (example of gender imbalance)!
2-5 females: 1 male!•
exacerbated by pregnancy!•
!
