Exam 1 Flashcards
All chromosomes apart from the sex chromosomes
Autosomes
A chromosome that is represented differently in the two different sexes
Sex chromosomes
Female homozygous for the recessive allele or males hemizygous for it display the recessive phenotype
X-linked recessive
heterozygous females and males hemizygous for the dominant allele express the dominant phenotype
X-linked dominant
Transcription factor needed for male-specific gene expression
SRY
PAR1 and PAR2, exist between the X and Y chromosomes
Pseudoautosomal regions
One of two X chromosomes in each female somatic cell is randomly inactivated
Random X inactivation hypothesis, Lyon hypothesis
Intermating group of individuals
Population
The relative frequency of a gene allele in a population
Gene Frequency
The relative frequency of a genotypic in a population
Genotypic Frequency
Relative frequency of a phenotype in a population
Phenotypic Frequency
The collection of alleles found in the members of a population
Gene pool
Describes the relationship of allele and genotype frequencies in populations
Hardy-Weinberg Law
In an “ideal” population that is infinitely large with random mating and not subject to any evolutionary forces allele and genotypic frequencies remain constant from one generation to the next
Hardy-Weinberg Equilibrium
Factor (gene) capable of masking the presence of a second factor (gene) in the expression of a phenotype
Dominant
Factor (gene) being masked by the dominant factor (gene)
Recessive
Heterozygote cannot be distinguished from the homozygous dominant
Complete Dominance
Heterozygote more closely resembles the homozygous dominant
Partial Dominance
The heterozygote is exactly halfway between the homozygous dominant and the homozygous recessive
No Dominance
The heterozygote exceeds the range established by the homozygous genotypes
Overdominance
Both alleles are expressed in separate and distinguishable manner
Codominance
The heterozygote exceeds the range established by the homozygous genotypes but can only be passed on from one direction
Example: Callipyge Sheep
Polar Overdominance
The proportion of individuals with a single gene mutation do not have an observable phenotype
Penetrance (incomplete)
Individuals with the same genotype exhibit varying degree in which the trait is expressed
Expressivity
Interaction among genes at different loci such that the expression of genes at one locus depends on the alleles present at one or more other loci. (masking-recessive)
Epistasis
Expression is absolutely limited to one sex
Sex-limited
The sex influences expression but is not limited to one sex
Sex-Influenced
Family trees, are a way of tracing the inheritance of traits in humans and animals
Pedigree
______ leads to extensive genetic variation
Independent assortment
Line in which animals of like phenotypes perpetuate the phenotypes in their offspring
Pure breed lines
A group of domestic animals with similar “homogeneous” appearances
Breed
A kind of breeding in which the parents with a particular phenotype produce offspring only with the same phenotype
True breeding
Alternative versions of genes
Alleles
Allows the genotypes phenotypes resulting from a cross to be visualized easily
Punnett square
Identical alleles
Homozygous
Two different alleles
Heterozygous
Trait shown by the F1 offspring
Dominant phenotype
Trait that was not apparent in the F1
Recessive Phenotype
Mendel proposed the theory of ______.
Particulate Inheritance
Mendel’s Laws
______ the separation of paired genes during germ cell formation.
______ the independent segregation of genes (chromosomes) during germ cell formation (Meiosis)
Segregation
Independent Assortment
2 things that contribute to genetic variation
Independent assortment
Recombination
Differences between meiosis and mitosis
Pairing and synapsis
Recombination
Segregation
The value of an individual as a (genetic) parent
Breeding value
Lightly packed or uncoiled DNA, is gene rich & under active transcription
Euchromatin
Tightly packed condensed areas of DNA, inactive because they either lack genes or contain genes that are repressed
Heterochromatin
Five types of Histones
H1, H2A, H2B, H3, and H4
Number of chromosomes Human Cattle Sheep Swine Cat Dog Horse Donkey Chicken
23 30 27 19 19 39 32 31 39
A classification for animals with similar genotypes for traits of interest
Biological type
Represents a dependent relationship between genotypes and environments
G x E interaction
Animals whose role is to be a parent; animals contributing genes to the next generation
Seedstock
Animals of one breed or line
Purebred
Group of related animals within a breed
Line
Process by which some individuals are more likely to survive and reproduce than others; process that determines which animals become parents
Selection
Selection that occurs in nature independent of deliberate human control
Natural selection
Selection that is under human control
Artificial selection
A system or set of rules determining which selected males will be mated to which selected females
Mating systems
Mating designed to correct in their progeny faults of one or both parents
Corrective mating
An intermediate level of performance that is optimal in terms of profitability and/or function
Intermediate optimum
Trait having discrete phenotypic classes but also having underlying continuous variation
Threshold trait
Trait measured only once during the lifetime of an individual
Single trait
Trait expressed more than once during the lifetime of an individual
Repeated trait
Traits measured on both sexes
Individual trait
Traits observed only in females
Maternal traits
Traits observed only in males
Parental traits
Study of the principles of inheritance in animals
Animal genetics
Application of the principles of animal genetics to improve livestock
Animal breeding
Branch of genetics that utilizes mathematical theory and statistics
Quantitative Genetics
Any observable or measurable characteristic of an individual
Trait
