{"id":883,"date":"2022-04-20T20:30:08","date_gmt":"2022-04-20T20:30:08","guid":{"rendered":"https:\/\/pressbooks.hcfl.edu\/bio1\/chapter\/key-terms-12\/"},"modified":"2025-08-29T19:10:12","modified_gmt":"2025-08-29T19:10:12","slug":"key-terms-12","status":"publish","type":"chapter","link":"https:\/\/pressbooks.hcfl.edu\/bio1\/chapter\/key-terms-12\/","title":{"raw":"Key Terms","rendered":"Key Terms"},"content":{"raw":"
\n \t
allele<\/dt>\n \t
gene variations that arise by mutation and exist at the same relative locations on homologous chromosomes<\/dd>\n<\/dl>\n
\n \t
autosomes<\/dt>\n \t
any of the non-sex chromosomes<\/dd>\n<\/dl>\n
\n \t
blending theory of inheritance<\/dt>\n \t
hypothetical inheritance pattern in which parental traits are blended together in the offspring to produce an intermediate physical appearance<\/dd>\n<\/dl>\n
\n \t
carriers<\/dt>\n \t
heterozygous individual or organism that carries a recessive allele that is not contributing to the phenotype. Relevant in medicine for recessive alleles that cause genetic disease(s) in homozygous offspring<\/dd>\n<\/dl>\n
\n \t
chromosomal basic of heredity<\/dt>\n \t
also known as Chromosomal Theory of Inheritance. A theory proposing that chromosomes are the genes\u2019 vehicles and that their behavior during meiosis is the physical basis of the inheritance patterns that Mendel observed<\/dd>\n<\/dl>\n
\n \t
codominance<\/dt>\n \t
in a heterozygote, complete and simultaneous expression of both alleles for the same characteristic<\/dd>\n<\/dl>\n
\n \t
continuous variation<\/dt>\n \t
inheritance pattern in which a character shows a range of trait values with small gradations rather than large gaps between them<\/dd>\n<\/dl>\n
\n \t
dihybrid<\/dt>\n \t
result of a cross between two true-breeding parents that express different traits for two characteristics<\/dd>\n<\/dl>\n
\n \t
discontinuous variation<\/dt>\n \t
inheritance pattern in which traits are distinct and are transmitted independently of one another<\/dd>\n<\/dl>\n
\n \t
dominant<\/dt>\n \t
trait which confers the same physical appearance whether an individual has two copies of the trait or one copy of the dominant trait and one copy of the recessive trait<\/dd>\n<\/dl>\n
\n \t
dominant lethal<\/dt>\n \t
inheritance pattern in which an allele is lethal both in the homozygote and the heterozygote; this allele can only be transmitted if the lethality phenotype occurs after reproductive age<\/dd>\n<\/dl>\n
\n \t
epistasis<\/dt>\n \t
antagonistic interaction between genes such that one gene masks or interferes with the expression of another<\/dd>\n<\/dl>\n
\n \t
F1<\/sub><\/dt>\n \t
first filial generation in a cross; the offspring of the parental generation<\/dd>\n<\/dl>\n
\n \t
F2<\/sub><\/dt>\n \t
second filial generation produced when F1<\/sub>\u00a0individuals are self-crossed or fertilized with each other<\/dd>\n<\/dl>\n
\n \t
genetics<\/dt>\n \t
the study of heredity<\/dd>\n<\/dl>\n
\n \t
genotype<\/dt>\n \t
underlying genetic makeup, consisting of both physically visible and non-expressed alleles, of an organism<\/dd>\n<\/dl>\n
\n \t
hemizygous<\/dt>\n \t
presence of only one allele for a characteristic, as in X-linkage; hemizygosity makes descriptions of dominance and recessiveness irrelevant<\/dd>\n<\/dl>\n
\n \t
heterozygous<\/dt>\n \t
having two different alleles for a given gene on the homologous chromosome<\/dd>\n<\/dl>\n
\n \t
homozygous<\/dt>\n \t
having two identical alleles for a given gene on the homologous chromosome<\/dd>\n<\/dl>\n
\n \t
hybridization<\/dt>\n \t
process of mating two individuals that differ with the goal of achieving a certain characteristic in their offspring<\/dd>\n<\/dl>\n
\n \t
incomplete dominance<\/dt>\n \t
in a heterozygote, expression of two contrasting alleles such that the individual displays an intermediate phenotype<\/dd>\n<\/dl>\n
\n \t
law of dominance<\/dt>\n \t
in a heterozygote, one trait will conceal the presence of another trait for the same characteristic<\/dd>\n<\/dl>\n
\n \t
law of independent assortment<\/dt>\n \t
genes do not influence each other with regard to sorting of alleles into gametes; every possible combination of alleles is equally likely to occur<\/dd>\n<\/dl>\n
\n \t
law of segregation<\/dt>\n \t
paired unit factors (i.e., genes) segregate equally into gametes such that offspring have an equal likelihood of inheriting any combination of factors<\/dd>\n<\/dl>\n
\n \t
linkage<\/dt>\n \t
phenomenon in which alleles that are located in close proximity to each other on the same chromosome are more likely to be inherited together<\/dd>\n<\/dl>\n
\n \t
Mendelian genetics<\/dt>\n \t
patterns of inheritance discovered by Gregor Mendel that include law of segregation, law of independent assortment, genotypes and phenotypes<\/dd>\n<\/dl>\n
\n \t
model system<\/dt>\n \t
species or biological system used to study a specific biological phenomenon to be applied to other different species<\/dd>\n<\/dl>\n
\n \t
monohybrid<\/dt>\n \t
result of a cross between two true-breeding parents that express different traits for only one characteristic<\/dd>\n<\/dl>\n
\n \t
P0<\/sub><\/dt>\n \t
parental generation in a cross<\/dd>\n<\/dl>\n
\n \t
phenotype<\/dt>\n \t
observable traits expressed by an organism<\/dd>\n<\/dl>\n
\n \t
product rule<\/dt>\n \t
probability of two independent events occurring simultaneously can be calculated by multiplying the individual probabilities of each event occurring alone<\/dd>\n<\/dl>\n
\n \t
Punnett square<\/dt>\n \t
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<\/dd>\n<\/dl>\n
\n \t
recessive<\/dt>\n \t
trait that appears \u201clatent\u201d or non-expressed when the individual also carries a dominant trait for that same characteristic; when present as two identical copies, the recessive trait is expressed<\/dd>\n<\/dl>\n
\n \t
recessive lethal<\/dt>\n \t
inheritance pattern in which an allele is only lethal in the homozygous form; the heterozygote may be normal or have some altered, nonlethal phenotype<\/dd>\n<\/dl>\n
\n \t
reciprocal cross<\/dt>\n \t
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 the other cross<\/dd>\n<\/dl>\n
\n \t
sex-linked<\/dt>\n \t
any gene on a sex chromosome<\/dd>\n<\/dl>\n
\n \t
sum rule<\/dt>\n \t
probability of the occurrence of at least one of two mutually exclusive events is the sum of their individual probabilities<\/dd>\n<\/dl>\n
\n \t
test cross<\/dt>\n \t
cross between a dominant expressing individual with an unknown genotype and a homozygous recessive individual; the offspring phenotypes indicate whether the unknown parent is heterozygous or homozygous for the dominant trait<\/dd>\n<\/dl>\n
\n \t
trait<\/dt>\n \t
variation in the physical appearance of a heritable characteristic<\/dd>\n<\/dl>\n
\n \t
true breeding<\/dt>\n \t
parental organisms that always produce offspring that look like the parent (because they are homozygous for that trait)<\/dd>\n<\/dl>\n
\n \t
wild type<\/dt>\n \t
term for most common phenotype or genotype among wild animals of a gene<\/dd>\n<\/dl>\n
\n \t
X-linked<\/dt>\n \t
gene present on the X, but not the Y chromosome<\/dd>\n<\/dl>","rendered":"
\n
allele<\/dt>\n
gene variations that arise by mutation and exist at the same relative locations on homologous chromosomes<\/dd>\n<\/dl>\n
\n
autosomes<\/dt>\n
any of the non-sex chromosomes<\/dd>\n<\/dl>\n
\n
blending theory of inheritance<\/dt>\n
hypothetical inheritance pattern in which parental traits are blended together in the offspring to produce an intermediate physical appearance<\/dd>\n<\/dl>\n
\n
carriers<\/dt>\n
heterozygous individual or organism that carries a recessive allele that is not contributing to the phenotype. Relevant in medicine for recessive alleles that cause genetic disease(s) in homozygous offspring<\/dd>\n<\/dl>\n
\n
chromosomal basic of heredity<\/dt>\n
also known as Chromosomal Theory of Inheritance. A theory proposing that chromosomes are the genes\u2019 vehicles and that their behavior during meiosis is the physical basis of the inheritance patterns that Mendel observed<\/dd>\n<\/dl>\n
\n
codominance<\/dt>\n
in a heterozygote, complete and simultaneous expression of both alleles for the same characteristic<\/dd>\n<\/dl>\n
\n
continuous variation<\/dt>\n
inheritance pattern in which a character shows a range of trait values with small gradations rather than large gaps between them<\/dd>\n<\/dl>\n
\n
dihybrid<\/dt>\n
result of a cross between two true-breeding parents that express different traits for two characteristics<\/dd>\n<\/dl>\n
\n
discontinuous variation<\/dt>\n
inheritance pattern in which traits are distinct and are transmitted independently of one another<\/dd>\n<\/dl>\n
\n
dominant<\/dt>\n
trait which confers the same physical appearance whether an individual has two copies of the trait or one copy of the dominant trait and one copy of the recessive trait<\/dd>\n<\/dl>\n
\n
dominant lethal<\/dt>\n
inheritance pattern in which an allele is lethal both in the homozygote and the heterozygote; this allele can only be transmitted if the lethality phenotype occurs after reproductive age<\/dd>\n<\/dl>\n
\n
epistasis<\/dt>\n
antagonistic interaction between genes such that one gene masks or interferes with the expression of another<\/dd>\n<\/dl>\n
\n
F1<\/sub><\/dt>\n
first filial generation in a cross; the offspring of the parental generation<\/dd>\n<\/dl>\n
\n
F2<\/sub><\/dt>\n
second filial generation produced when F1<\/sub>\u00a0individuals are self-crossed or fertilized with each other<\/dd>\n<\/dl>\n
\n
genetics<\/dt>\n
the study of heredity<\/dd>\n<\/dl>\n
\n
genotype<\/dt>\n
underlying genetic makeup, consisting of both physically visible and non-expressed alleles, of an organism<\/dd>\n<\/dl>\n
\n
hemizygous<\/dt>\n
presence of only one allele for a characteristic, as in X-linkage; hemizygosity makes descriptions of dominance and recessiveness irrelevant<\/dd>\n<\/dl>\n
\n
heterozygous<\/dt>\n
having two different alleles for a given gene on the homologous chromosome<\/dd>\n<\/dl>\n
\n
homozygous<\/dt>\n
having two identical alleles for a given gene on the homologous chromosome<\/dd>\n<\/dl>\n
\n
hybridization<\/dt>\n
process of mating two individuals that differ with the goal of achieving a certain characteristic in their offspring<\/dd>\n<\/dl>\n
\n
incomplete dominance<\/dt>\n
in a heterozygote, expression of two contrasting alleles such that the individual displays an intermediate phenotype<\/dd>\n<\/dl>\n
\n
law of dominance<\/dt>\n
in a heterozygote, one trait will conceal the presence of another trait for the same characteristic<\/dd>\n<\/dl>\n
\n
law of independent assortment<\/dt>\n
genes do not influence each other with regard to sorting of alleles into gametes; every possible combination of alleles is equally likely to occur<\/dd>\n<\/dl>\n
\n
law of segregation<\/dt>\n
paired unit factors (i.e., genes) segregate equally into gametes such that offspring have an equal likelihood of inheriting any combination of factors<\/dd>\n<\/dl>\n
\n
linkage<\/dt>\n
phenomenon in which alleles that are located in close proximity to each other on the same chromosome are more likely to be inherited together<\/dd>\n<\/dl>\n
\n
Mendelian genetics<\/dt>\n
patterns of inheritance discovered by Gregor Mendel that include law of segregation, law of independent assortment, genotypes and phenotypes<\/dd>\n<\/dl>\n
\n
model system<\/dt>\n
species or biological system used to study a specific biological phenomenon to be applied to other different species<\/dd>\n<\/dl>\n
\n
monohybrid<\/dt>\n
result of a cross between two true-breeding parents that express different traits for only one characteristic<\/dd>\n<\/dl>\n
\n
P0<\/sub><\/dt>\n
parental generation in a cross<\/dd>\n<\/dl>\n
\n
phenotype<\/dt>\n
observable traits expressed by an organism<\/dd>\n<\/dl>\n
\n
product rule<\/dt>\n
probability of two independent events occurring simultaneously can be calculated by multiplying the individual probabilities of each event occurring alone<\/dd>\n<\/dl>\n
\n
Punnett square<\/dt>\n
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<\/dd>\n<\/dl>\n
\n
recessive<\/dt>\n
trait that appears \u201clatent\u201d or non-expressed when the individual also carries a dominant trait for that same characteristic; when present as two identical copies, the recessive trait is expressed<\/dd>\n<\/dl>\n
\n
recessive lethal<\/dt>\n
inheritance pattern in which an allele is only lethal in the homozygous form; the heterozygote may be normal or have some altered, nonlethal phenotype<\/dd>\n<\/dl>\n
\n
reciprocal cross<\/dt>\n
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 the other cross<\/dd>\n<\/dl>\n
\n
sex-linked<\/dt>\n
any gene on a sex chromosome<\/dd>\n<\/dl>\n
\n
sum rule<\/dt>\n
probability of the occurrence of at least one of two mutually exclusive events is the sum of their individual probabilities<\/dd>\n<\/dl>\n
\n
test cross<\/dt>\n
cross between a dominant expressing individual with an unknown genotype and a homozygous recessive individual; the offspring phenotypes indicate whether the unknown parent is heterozygous or homozygous for the dominant trait<\/dd>\n<\/dl>\n
\n
trait<\/dt>\n
variation in the physical appearance of a heritable characteristic<\/dd>\n<\/dl>\n
\n
true breeding<\/dt>\n
parental organisms that always produce offspring that look like the parent (because they are homozygous for that trait)<\/dd>\n<\/dl>\n
\n
wild type<\/dt>\n
term for most common phenotype or genotype among wild animals of a gene<\/dd>\n<\/dl>\n
\n
X-linked<\/dt>\n
gene present on the X, but not the Y chromosome<\/dd>\n<\/dl>\n","protected":false},"author":130,"menu_order":7,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["jung-choi","mary-ann-clark","matthew-douglas"],"pb_section_license":"cc-by"},"chapter-type":[],"contributor":[92,93,94],"license":[53],"class_list":["post-883","chapter","type-chapter","status-publish","hentry","contributor-jung-choi","contributor-mary-ann-clark","contributor-matthew-douglas","license-cc-by"],"part":847,"_links":{"self":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/883","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/users\/130"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/883\/revisions"}],"predecessor-version":[{"id":884,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/883\/revisions\/884"}],"part":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/parts\/847"}],"metadata":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/883\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/media?parent=883"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapter-type?post=883"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/contributor?post=883"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/license?post=883"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}