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