Genetics / Reproduction Flashcards
Gene
Segment of DNA chromosome that provide the code for specific proteins or regulate expression of other genes
Allele
Form of a gene that may be present
Polygenic Inheritance
Phenotypes that are influenced by multiple genes
Co-Dominance
A gene pair in which both are expressed with a blending of the phenotypes of 2 alleles
Co-dominance example
Cross between red & white carnation produces pink flower
Epistatic genes
Genes that modify or prevent the expression of other genes
Incomplete dominance
Pair of genes in which both are expressed with both phenotypes visible in the offspring
Example of incomplete dominance
Cross between a black chicken and a white chicken produces a spotted black & white chicken
How are offspring of 2 purebred parents described
F1 / first filial generation
Monohybrid cross
Predicts genotype & phenotype of offspring that differ in genotype for a single trait
Dihybrid cross
Predicts offspring of 2 individuals that differ in genotype for 2 traits that are inherited independently
Phenotype ratio for dihybrid cross
9:3:3:1
Autosomal
All genes that are not located on the sex chromosomes
What happens when a male inherits an X-linked recessive allele
It is always expressed
Autosomal dominant
Dominant alleles will transmit to every generation unless the penetrance is interrupted
Autosomal Recessive
Parents and remote relatives of affected individual will not be affected / skips generations
What percentage of progeny will be affected by autosomal recessive genes
About 25%
Pedigree chart
Diagram used to track inheritance of specific traits
Test cross
Determines genotype of particular phenotypes
Backcross
Pairing of an F1 generation hybrid with an organism whose genotype is identical to the parental strain
Outbreeding / Random breeding
Mating of other, unrelated, strains to increase number of heterozygotes
What type of breeding keeps the largest gene pool
Outbreeding / random breeding
What type of breeding keeps fitness traits at high levels
Outbreeding / random breeding
Assortative mating
Mating of individuals that are phenotypically similar
What type of breeding system chooses individuals for their phenotype
Assortative mating
Inbreeding
Minimum of 20 consecutive brother-sister matings
What breeding system is designed to reduce heterozygosity
Inbreeding
Inbreeding depression
When an individual becomes homozygous
Ways to reduce inbreeding depression
Introduce new sire with as many desirable traits as possible
Outcross within breeding population
Heterosis / Hybrid Vigor
F1 generation produced by crossing 2 different inbred strains
Line breeding
System of inbreeding closely related individuals to guarantee similar traits in offspring
Harem Mating
When 1 male is mated to, and generally housed with, at least 5 females
Transgenic
Alters genetic makeup by transplanting a specific DNA strand into morula or by exposing embryo to mutating factors
What is the first generation of transgenic breeding referred to as
F0
Founder animal
Mutation
Any change in the DNA sequence of a gene
Genetic Mutation
Change in the DNA sequence of a gene contained in a gamete
Translocation
Breakage of 2 chromosomes resulting in repair in an abnormal arrangement
Deletion
Part or all of a chromosome is missing
Duplication
An allele is duplicated
Lethal Genes
A gene that will cause the death of an embryo or serious impairment or death sometime after birth
Usually homozygous recessive
Semilethal Gene
Causes individual to have abnormal traits
Incomplete dominance lethal gene
Results in death in homozygous individuals
Heterozygous individuals will show clinical signs
Age of puberty in female cats
7-12 months
What factors affect age of puberty in female cats
Weight
Hair coat - long reaches later
Hours of daylight
Season of birth
Age of puberty in male cat
9 months
Male cat accessory sex glands
Prostate
Bulbourethral / cowper
Methods for feline semen collection
Artificial vagina - only about 20% can be trained
Electroejaculation
Natural breeding
What type of estrous cycle do cats have
Seasonally polyestrous
What type of placenta do cats have
Zonary
How much / often should kittens be hand fed
15-20% bodyweight in 4 servings
At what age can kittens transition to dry food
4 weeks
Weaning age for kittens
5-8 weeks
Age of puberty in female dogs
8 months
Why should female dogs not be bred on first estrous cycle
They are sexually mature, but not anatomically mature
What should all breeding dogs be tested for
Brucella canis
What can B. canis cause in breeding dogs
Abortion
Fetal resorption
Infertility
Accessory sex glands in the dog
Prostate
Ways to collect dog semen
Teaser bitch
Masturbation
Electroejaculation
Which method of collecting dog semen is most common
Teaser bitch
What method of dog semen collection is NOT commonly used
Electroejaculation
Which method of dog semen collection requires anesthesia
Electroejaculation
What type of estrous cycle does a dog have
Non-seasonal, twice per year, no true estrous cycle
What type of placenta do dogs have
Zonary
When can puppies begin to eat solid food
4 weeks
What age should puppies be weaned
6-8 weeks
Age of puberty mare
12-24 months
Age of puberty stallion
12-18 months
Stallion accessory sex glands
Sminal vesicles
Prostate
Bulbourethral / cowpers
Equine semen collection techniques
Artificial vagina / phantom
Condoms
Vaginal collection
Dismount sample
What is the most common method to collect stallion semen
Artificial vagina / phantom
Type of estrous cycle for mares
Seasonally polyestrous
What type of placenta do horses have
Diffuse & microcotyledonary
How long does the CL produce progesterone in a pregnant mare
120 - 150 days
Age of puberty in heifers
9-10 months
What factors influence puberty in heifers
Weight
When should a heifer be bred in relation to age / weight
15 months, 1000lbs
Age of puberty for bulls (cow)
7-18 months
Bull (cow) accessory sex glands
Vesicular glands
Prostate
Bulbourethral
What disease can cause abortion in cows
Q fever
Causative agent for Q fever
Coxiella burnetii
Techniques for bull (cow) semen collection
Electroejaculation
Massage
Artificial vagina
What type of estrous cycle do cows have
Non-seasonal polyestrous
What type of placenta do cows have
Codyledonary
What is a ‘Free Martin’
Female twin of a male calf
Infertile and hermaphroditic
Doe (goat) age of puberty
6-8 months
At what weight should a female goat be first bred
At least 60-70% of adult body weight
Age of puberty in buck (goat)
4-5 months
Buck (goat) accessory sex glands
Seminal vesicles
Prostate
Bulbourethral / cowpers
Buck semen collection methods
Artifical vagina
Bailey Ejaculator / electroejaculation
What method is not commonly used for buck semen collection
Bailey ejaculator
Why is the Bailey ejaculator not used commonly in goats?
Because of the response of the buck, increased vocalizations and excessive muscle contractions
What type of estrous cycle do goats have
Seasonally polyestrous
How can the estrous cycle be controlled in goats
Presentation of a male
Prostaglandins
Progestins
What do prostaglandins do
Induce ovulation
What do progestins do
Delay ovulation
What type of placenta do goats have
Codyledonary
What percentage of goat births are dystocai
3-5%
At what age can goats be weaned
3 months
Age of puberty in ewe
6-7 months
At what weight should a ewe first be bred
65% of mature body weight
Age of puberty in ram
6 months
At what age should a ram be first bred
24 months
Ram accessory sex glands
Seminal vesicles
Prostate
Bulbourethral
Ram semen collection techniques
Electroejaculation
What type of estrous cycle do ewes have
Seasonally polyestrous
Short day breeders
Whitten Effect
Introducing a ram to ewes shortly before onset of breeding season to begin cycling within 5-6 days
Ewe flushing
Increasing dietary intake before breeding to increase the number of mature follicles / follicles ruptured
How much should ewes nutrition be increased in last trimester
50%
What type of placenta do ewes have
Codyledonary
What will happen after 2-3 hours of non-productive labor in the ewe
The cervix will close
Common lamb defects
Cleft palate
Umbilical hernia
Entropion
What should be supplemented to the ewe or lamb (if not given to the ewe)
Selenium
Vitamin E
Age / weight of puberty in sows
250 lbs 200 days (4-6 months)
What affects onset of puberty in sows
Genetics
Environment
Age of puberty in boars
5-7 months
Age of full maturity in boars
2 years
Boar accessory sex glands
Seminal vesicles
Prostate
Bulbourethral / cowpers
Boar semen collection techniques
Gloved hand
Teaser sow
What type of estrous cycle do pigs have
Non-seasonal polyestrous
What type of placenta do pigs have
Diffuse
At what age are pigs weaned
3-5 weeks
What should every piglet receive supplementation of
200mg iron dextran