ANS 150 Hormones, Dominance, Cell Types, Definitions

Estrus

Reproductive system without Pregnancy

“us” - (us in the exact moment 😉 )

Estrous

The whole reproductive system

“ous” - (like various or continuous)

Epistasis

genes interact with each other

Epigenetics

gene expression changes without changing the DNA sequence

(ex. Twins have the same DNA but can develop different diseases/sicknesses as they live)

Partial Dominance

Heterozygous Alleles mix and gene shows dominant + recessive traits

(ex. Mother w/ curly hair + Father w/ straight hair = Child with wavy hair)

Complete Dominance

Heterozygous Alleles show only Dominant Trait

(ex. Brown eyes = B, Blue eyes = b, Bb will always show Brown eyes)

Over dominance

Heterozygote shows dominant trait in an even more dominant way than dominant

(Heterozygote-Bb has higher fitness/survival rate than homozygote-BB,bb)

Similarity between Partial Dominance, Complete Dominance, & Over Dominance

They are 100% Heritable

Difference between Partial Dominance, Complete Dominance, & Over Dominance

Heterozygote (Rr) could be

• Dominant

• Mixed

• Extra Dominant

How the heterozygote expresses phenotype compared to the homozygote

Unipotent

Ability to develop into one cell type

(ex. Epidermal stem cells will only divide to create new skin cells)

Pluripotent

Ability to develop into any cell type

(ex. a cell that can become anything but hasn’t specialized into one role yet)

Totipotent

A cell that can develop into a whole organism

(ex. Zygote can develop into any organism including the placenta at the 2-cell and 4-cell stages)

Order of the “potent” cells

Totipotent » Pluripotent » Unipotent

FSH (Follicle Stimulating Hormone)

When/Where: Pituitary Gland » Beginning of Estrus

Function: Stimulates each phase of follicle cycle, especially early periods

LH (Lutenizing Hormone)

When/Where: Pituitary Gland » Beginning of follicle cycle (Growth, Ovulation, CL)

Function: Stimulates follicle growth + CL, Stimulates Ovulation, Puberty Rate limiter

Estrogen

When/Where: Growing follicles, Placenta, Embryos, High before Ovulation

Function: Supports Estrus, Sopports Parturition, Prepares female for breeding, Influences mating behavior

Progesterone

When/Where: Produced in CL

Function: Maintains Pregnancy, Inhibits gonadotrophin production (LH + FSH)

Prostaglandin F2Alpha

When/Where: Produced in the Uterus (Not pregnant, Estrous)

Function: Regresses CL (CL » CA), Causes Uterine Contractions

Prolactin

When/Where: Pituitary Gland » Neural Reflex Arc (Suckling sends signal to brain » Prolactin + Oxytocin release towards mammary glands)

Function: prepares milk for next meal, makes/builds milk supply

Oxytocin

When/Where: Stored in Hypothalamus, Produced from Pituitary gland, Neural Reflex Arc (Suckling sends signal to brain » Prolactin + Oxytocin release towards mammary glands)

(Oxytocin travels down nerve fibers from hypothalamus to pituitary gland for when it is needed)

Function: release of milk, stimulates contractions

FSH + LH (MALES)

When/Where: Pituitary Gland

Function: Production of sperm

How do the genes on chromosomes produce the phenotypes that we see and measure in animals?

mRNA » Protein » Phenotypes

What is the difference between epistasis and epigenetics from a genetic perspective?

Genotypes are the same for epigenetics, but the genes are turned off (not producing proteins).

Genotypes are different for epistasis and all the genes are on (producing proteins).

What happens to most of the follicles that start to grow on the ovaries in females?

They become atretic or die before ovulation.

Milk production has a heritability of 50% while calving ease has a heritability of 15%. Which one could be

improved the most with good management? Please provide an explanation for your answer for full credit. (6

points).

The heritability of calving ease is 15% which means 85% of its variation is to variation in the environment or

management, so improving good management would be more likely to improve it compared with milk

production for which 50% of its variation is due to variation in the environment or management.

What are the two reasons that we discussed in class why management of females in late gestation is so

important?

1. fetus could have birth weight/ developmental issues

2. risk having early parturition

List all the phases of the female reproductive cycle when both estrogen and progesterone are low.

Lactation

What would happen if a veterinarian accidently gave a bull progesterone?

LH and FSH would decrease which would cause both sperm production and testosterone (libido) to decrease.

List all the possible sources of estrogens in female swine.

Follicles, placenta and embryos