How does inheritance work?
How is the allele inherited?
-in an all or nothing pattern -traits are not blended in the offspring and as distinct traits
Codominance
-more than two alleles for the same characteristics so they are both expressed equally -in a heterozygote, complete and simultaneous expression of both alleles for same characteristics
Incomplete dominance
-neither allele is 100% dominant so the phenotype is a mix -expression of two contrasting alleles such that the individual displays an intermediate phenotype
In any given trait, how many alleles can you have?
Never more than two and one from each parent
Gregor Mendel
Set the framework for genetics and heredity fundamentals revealed it thanks to his previous work
Test cross
a cross between dominant expressing individual with an unknown genotype and a homozygous recessive individual; the offspring phenotypes indicate whether the unknown parent is heter or homozygous for the dominant trait
X-Linked
a gene present on the X chromosome but not the Y chromosome
Chromosomes
a gene that is at a particular location on a particular chromosome
Reciprocal cross
a paired cross in which the respective traits of the male and female in one cross become the respective traits of the female and male in other cross
Linkage
a phenomenon in which alleles that are located in close proximity to each other on the same chromosome are more likely to be inherited together
Continuous variation
a variation in a characteristics in which individuals show a range of traits with small differences between them
Trait
a variation in an inherited characteristic
Punnet Square
a visual representation of a cross between two individuals in which the gametes of each individual are denoted along the top and side of a grid, respectively, and the possible zygotic genotypes are recombined at each box in the grid
Epigenetic tags
acts as a cellular memory since they are passed along to daughter cells as cells divide
Epistasis
an interaction between genes such that one gene masks or interferes with the expression of another
Defective connective tissue
caused by a single gene
Dominant
describes a trait that masks the expression of another trait when both versions of the gene are present in an individual
Recessive
describes a trait whose expression is masked by another trait when the alleles for both traits are present in an individual
Law of Independent Assortment
genes do not influence each other with regard to sorting of alleles in gametes; every possible combination of alleles is equally likely to occur
Law of Independent Assortment
genes do not influence each other with regard to sorting of alleles into gametes; every possible combination of alleles is equally likely to occur
Heterozygous
having two different alleles for a given gene on the homologous chromosomes
Homoszygous
having two identical alleles for a given gene on the homologous chromosomes
What did the process help with?
helped formed the basis of classical or mendelian genetics
Law of Dominance
in a heterozygote, one trait will conceal the presence of another trait for the same characteristic
Locus
location on the chromosome
Polygenic Inheritance
more than one gene contributes to one characteristic
Phenotype
observable expressed trait
Pleiotropy
occurs when one gene causes several different phenotypes
Homologous Chromosomes
one comes from mom and dad and carry the same gene as the loci; identical alleles one both from chromatids or halves from each parent
Monohybrid Cross
one genotype and phenotype to the other
Allele
one of two or more variants of a gene that determines a particular trait for a characteristic
Genotype
organisms underlying genetic makeup that consists of both alleles
Law of Segregation
paired unit factors segregate equally into gametes such that offspring have an equal likelihood of inheriting any combination of factors
Recombination
process during meiosis in which homologous chromosomes exchange linear segments of genetic material, thereby dramatiacally increasing genetic variation in the offspring and separating linked genes
Gene
region of DNA that conveys inheritance information for particular characteristics; come in different versions
F1
the first filial generation in a cross; the offspring of the parental generation
Wild types
the most commonly occurring genotype or phenotype for a given characteristic found in a population
P
the parental generation in a cross
Hemizygous
the presence of only one allele for a characteristic, as in X-linkage; makes descriptions of dominance and recessiveness irrelevant
Hybridization
the process of mating two individuals that differ with the goal of achieving a certain characteristic in their offspring
Monohybrid
the result of a cross between two true breeding parents that express different traits for only one characteristic
Dihybrid
the result of a cross between two true breeding parents that express different traits for two characteristics
F2
the second filial generation in a cross; the offspring of the parental generation
What was discovered about traits?
traits can be passed from parents to offspring
Marfin Syndrome
unusually tall, thin, long limbs and fingers, near sighted and more likely to suffer a ruptured arota