Test 2: Lecture 20: Factors Flashcards
Developmental (congenital) defects fall into 2 general categories:
genetic
environmental (teratogenic)
Variants at a single locus
alleles
heterozygous animals show which phenotype
dominant allele
phenotype only in homozygous animal
recessive
ABO blood groups: AB type is an example of what type of genotype-phenotype alleles
co dominant
intermediate phenotype in heterozygous,
partially dominant
another name for of partially dominant allele
Haploinsufficiency
explain partial/incomplete dominance and what is another name for this?
the heterozygote displays a intermediate phenotype
(one of which is homozygous dominant, and the other of which is homozygous recessive
example: pink flower, stranger thing kid
haploinsufficiency
co dominance of alleles
occurs when the phenotypes of both parents are simultaneously expressed in the same offspring organism.
blood typing
albinism is an example of ___ . What gene is affected?
autosomal recessive
tyrosinase
dwarfism in chickens is a ___ mutation
sex linked
ZZ (male)
ZW (female)
myotonia congenita is a mutation in what gene? and what type of mutation
chloride channel
autosomal recessive or dominant
X linked muscular dystrophy is a ___ mutation
sex linked XX/XY
dystrophin
mutation in RYR1 gene leads to what?
malignant hyperthermia in pigs
dominant negative activity
1 dominant copy and 1 mutated copy C730G
Autosomal dominant mutations in ryanodine receptor (RYR1, a calcium channel in muscle)
chromosomal abnormalities can be observed ___
cytologically
(spread out chromosomes on slide and look what is wrong)
___ is an uneven number of chromosomes
aneuploidy
example of monosomy
turner syndrome (XO)
example of trisomy
down syndrome (trisomy 21)
chromosomal rearrangements can be :
deletions, inversions, translocations
Robertsonian translocations t(1;29)-common and t(14;20)-rare
Animals often viable, but not ___
fertile.
happens in cattle
Selection for a single phenotypic trait during breeding can have ___ genetic consequences
deleterious
example of single trait selection leading to bad outcome
aggressive rapist roosters
it is believed that continuous selection for large breast size in the population resulted in the inability of the rooster to breed.
___ are agents that can cause a permanent alteration to structure or function of an embryo or fetus
teratogen
___ are therapeutic drug side effects
iatrogenesis
Some examples of teratogens
Environmental pollutants
Therapeutic drug side effects (iatrogenesis)
Poisonous plants and fungus + Infectious agents
Infection (bacterial/viral/parasitic)
Ionizing radiation
Maternal metabolic imbalance (phenylketonurea)
Wilson’s six principles of teratology
Susceptibility depends on ___of conceptus
genotype
Wilson’s six principles of teratology
Susceptibility varies with ___
developmental stage
Wilson’s six principles of teratology
Manifestations of deviant development increase in frequency and degree as ___increases from No Observable Adverse
dosage
Effect Level (NOAEL) to 100: lethality (LD100)
Four manifestations of deviant development:
death
malformation
growth retardation
functional defect
when is the embryo most susceptible to chemical teratogens
gastrulation- organogenesis
late developing structures such as ___ remain susceptible until late in gestation
palate
parts of urogenital/repro system
cerebellum
mycotoxins are
fungal metabolites
may be found in fungal infected feed
How to detect teratogen
HPLC-MS/MS (zearalenone, aflatoxin patulin (high pressure liquid chromatography/tandem mass spectrometry)
Colorimetric enzymatic assays, kits (aflatoxin)
latrogenic teratogens are
side effects to therapeutic drugs
types of teratogens
environmental pollutants
mycotoxins: fungal metabolites
iatrogenic (side effect to therapeutic drugs
poisonous plants
viruses
bacteria
protozoa
metabolic/ dietary effects
immunotolerance
persistent infection of offspring, not always readily noted, helps maintain disease in population!
Feline Panleukopenia V. is often ___
parvoviruses often teratogenic
Teratogen
excess Vit A can lead to ___
decreased Vit A can lead to ___
(a) deficiency-blindness
(b) excess- cranio-caudal axis and limb formation in embryos.
* RA can alter Hox gene expression, neural crest migration. RA dietary supplementation →CNS defects, cleft palate, thymic aplasia, heart abnormalities*.
