Improvement and Control of Traits Flashcards
◼ Transmitted from generation to generation
without skipping
◼ Every affected offspring has at least one affected
parent, except for new mutants
◼ Normal offspring from affected parents produce
only normal offspring when mated to normals
◼ Approximately equal numbers of males and
females are affected
Autosomal Dominant
◼ Inheritance of a disorder may skip generations
◼ All offspring of two affected parents are affected
◼ Approximately equal number of males and females are affected
◼ Carriers who usually mate with homozygous normals produce one-half carriers among their offspring
Autosomal Recessive
◼ Affected males when mated to normal females transmit the disorder to all their daughters but none to their sons.
◼ If the disorder is common, affected females when mated to normal males transmit the disorder to an average of ½ of their sons and ½ of their daughters
◼ If the disorder is rare, its incidence in females is approximately twice than in males
◼ Every affected offspring has at least one affected parent, except in new mutants
X-linked Dominant
◼ Inheritance of a disorder may skip generations
◼ All offspring of two affected parents are affected
◼ Incidence is lower in females than in males, with the incidence of the disorder in females approximately the square of the incidence in males in the general population.
X-linked Recessive
◼ Selection may be practiced for two or more traits at a time.
◼ A minimum standard is set that an animal must meet in order to be saved for breeding purposes. Failure to meet the minimum standard results in rejection of the animal.
Tandem Method
Involves separate determination of the value for each traits selected for, and the addition of these values gives a total score for all of the traits.
Selection Index
Mating of animals that are more closely related or more alike, resulting in progenies that are more homozygous than
their parents.
Inbreeding
Mating of animals that are less alike or less closely related, resulting in progenies that are more heterozygous than their parents.
Outbreeding
Proportion of identical genes that two animals have because they are members of the same family.
Relationship
Is the probability that the two genes present at a locus in that individual are identical by descent
Inbreeding Coefficient
◼ Exists between individuals and ancestors and between individuals and descendants.
◼ An individual is related to a parent because ½ of that individual’s genes were obtained from the parent.
Direct Relationship
Ancestor appears more than once in the pedigree; total relationship is the sum of the independent contributions from each pathway of direct descent
Line Breeding
◼ It exists between two individuals due to genetic contribution of a common ancestor.
◼ Two animals may be related because they received identical genes from same parent, grandparent or other common ancestor
Collateral Relationship
Involves mating of closely related animals that can be traced to more than one common ancestor.
Intensive Inbreeding
A kind of inbreeding where the relatives being mated are chosen because of a particular common ancestor.
Linebreeding
