* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Animal Genetics
Survey
Document related concepts
Inbreeding avoidance wikipedia , lookup
Human genetic variation wikipedia , lookup
Medical genetics wikipedia , lookup
Genetic testing wikipedia , lookup
Public health genomics wikipedia , lookup
Genome (book) wikipedia , lookup
Population genetics wikipedia , lookup
Koinophilia wikipedia , lookup
Designer baby wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Behavioural genetics wikipedia , lookup
Genetic engineering wikipedia , lookup
History of genetic engineering wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Microevolution wikipedia , lookup
Transcript
Animal Genetics Natural Selection an organisms ability to SURVIVE and pass on its GENETIC information to its offspring. Artificial Selection HUMAN control over organisms passing on their GENETIC information. Heredity the POTENTIAL an organism has to show certain TRAITS due to its GENETIC information Environment the EXTERNAL conditions that affect the traits and PERFORMANCE of an animal Environment vs. Heredity An organism's traits and performance are a sum total of its ENVIRONMENT acting upon its GENETIC information. Environment vs. Heredity Some TRAITS are influenced more by an organism's ENVIRONMENT than by its GENETICS, while others are influenced more by genetics. Heritability The percentage that a trait is affected by its genetic information is called HERITABILITY. A heritability factor of 0.0 means that a trait is influenced very little by genetic information A heritability factor of 1.0 means that a trait is influenced very little by the environment. Examples of Heritability Birth Weight = .40 Weaning Weight = .30 Multiple Births = 0.0 - 0.10 Dressing Percentage = .60 Adaptability The ability of a BREED to become SUITABLE to specific environmental conditions Type a group of ANIMALS that are grouped together according to the PRODUCTS they produce Examples -- Beef type cattle, Dairy type cattle, Wool type sheep, Mutton type sheep Species a group of ORGANISMS that have several common CHARACTERISTICS that differentiate them from others. Scientific Names of Species Cattle: Bos taurus, Bos indicus Sheep: Ovis aires Swine: Sui suidae Horse: Euquis caballus Chickens: Galus galus Breed animals having a common ORIGIN and CHARACTERISTICS that distinguish them from other groups within the same SPECIES. Purebred individuals within a BREED. They must have all of the CHARACTERISTICS of the breed and have a recorded PEDIGREE. Pedigree a record of an individual's ANCESTRY. Breeds of Cattle Angus Angus Hereford Charolais Charolais Brahman Brahman Shorthorn Shorthorn Simmental Simmental Salers Salers Texas Longhorn Red Angus Limousin Belted Galloway Beefmaster Holstein-Friesian Holstein-Friesian Guernsey Jersey Breeds of Sheep Rambouillet Rambouillet Columbia Suffolk Suffolk Hampshire Merino Dorset Lincoln Breeds of Swine Duroc Hampshire Chesterwhite Yorkshire Landrace Production of Sex Cells (Meiosis) 1. SIMILAR events to mitosis 2. Occurs ONLY in the TESTES and OVARIES to produce egg and sperm cells. 3. REDUCES the NUMBER of chromosomes to half the normal number. 4. ONE replication followed by TWO cell divisions. Meiosis FERTILIZATION the union of the egg and sperm nuclei restores the normal chromosome number. ZYGOTE a fertilized egg SPERMATOGENESIS 1. occurs in TESTES 2. EQUALLY sized cells 3. FOUR sperm cells produced Spermatogenesis OOGENESIS 1. occurs in OVARIES 2. DIFFERENT sized cells 3. ONE egg cell produced and three POLAR bodies Oogenesis Patterns of Inheritance DOMINANT the trait that SHOWS in a cross between two true-breeding parents Example in Cattle -- Black coat color, polled Example in Sheep -- White wool Example in Swine -- Black hair Recessive the trait that is HIDDEN in a cross between two individuals. Example in Cattle -- Red coat color, horns, dwarfism Example in Sheep -- Black wool Example in Swine -- Red hair PHENOTYPE the OUTWARD appearance of the organism Genotype the actual GENE MAKEUP of an organism Homozygous when both of the genes (letters) in the pair are the SAME Example -- TT or tt Heterozygous when both of the genes (letters) in the pair are DIFFERENT Example -- Tt Incomplete Dominance The genes are neither dominant nor recessive, but are equals Example -- Shorthorn Cattle –WW=White –RR=Red, –RW=Roan Types of Mating Systems Purebred Inbreeding Linebreeding Outcrossing Grading up Crossbreeding Hybrid vigor increased performance of offspring over that of the parents when unrelated individuals are mated. Heterosis Performance Pedigrees summarizes a particular animal's own performance records as well as records of ancestors, siblings, and progeny. Progeny = offspring EPD EXPECTED PROGENY DIFFERENCE an INDICATION of the amount of GENETIC merit that an animal will pass on to its offspring. EPD example a bull with an EPD for weaning weight of +25.0 pounds means that the bull's offspring should average 25.0 pounds more at 205 days of age than offspring of a bull with an EPD for weaning weight of 0.0 pounds. EPD Abbreviations BW = Birth Weight WW = Weaning Weight (205 days of age) YW = Yearling Weight (365 days of age) milk = maternal milking ability expressed in pounds of calf weaned.