BIO-1120: Chapter 14

a rule of probability stating that the probability of any one of two or more mutually exclusive events occurring can be determined by adding their individual probabilities

any of the alternative versions of a gene that may produce distinguishable phenotypic effects

a technique associated with prenatal diagnosis in which amniotic fluid is obtained by aspiration from a needle inserted into the uterus; the fluid and the fetal cells it contains are analyzed to detect certain genetic and congenital defects in the fetus

in genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder; the heterozygote is generally phenotypically normal for the disorder but can pass on the recessive allele to offspring

an observable heritable feature that may vary among individuals

a technique associated with prenatal diagnosis in which a small sample of the fetal portion of the placenta is removed for analysis to detect certain genetic and congenital defects in the fetus

the situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways

the situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable

a human genetic disorder caused by a recessive allele for a chloride channel protein; characterized by an excessive secretion of mucus and consequent vulnerability to infection; fatal if untreated

an organism that is heterozygous with respect to two genes of interest; all of the offspring from a cross between parents doubly homozygous for different alleles are dihybrids; for example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb

a cross between two organisms that are each heterozygous for both of the characters being followed (or the self-pollination of a plant that is heterozygous for both characters

an allele that is fully expressed in the phenotype of a hertozygote

a type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited gene

the first filial, hybrid (heterozygous) offspring arising from a parental (P generation) cross

the offspring resulting from interbreeding (or self-pollination) of the hybrid F₁ Generation

the genetic makeup, or set of alleles, of an organism

having two different alleles for a given gene

having two identical alleles for a given gene

a human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20 years after onset of symptoms

in genetics, the mating, or crossing, of two true-breeding varieties

the situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele

Mendel's second law, stating that each pair of alleles segregates, or assorts, independently of each other pairs of homologous chromosomes or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes

Mendel's first law, stating that the two alleles in a pair of segregate (separate from each other) into different gametes during gamete formation

an organism that is heterozygous with respect to a single gene of interest; all the offspring from a cross between parents homozygous for different alleles are monohyrbids; for example, parents of genotypes AA and aa produce a monohybrid of genotype Aa

a cross between two organisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant)

referring to a phenotypic character that is influenced by multiple genes and environmental factors

a rule of probability stating that the probability of two or more indepedent events occurring together can bee determined by multiplying their individual probabilities

a diagram of a famaily tree with conventional symbols, showing the occurrence of heritable characters in parents and offspring over multiple generations

the true-breeding (homozygous) parent individuals from which F₁ hybrid offspring are derived in studies of inheritance; P stands for "parental"

the observable physical and physiological traits of an organism, which are determined by its genetic makeup

the ability of a single gene to have multiple effects

an additive effect of two or more genes on a single phenotypic character

a diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of know genotype

a heritable feature that varies continuously over a range rather than in an either-or fashion

an allele whose phenotypic effect is not observed in a heterozygote

a recessively inherited human blood disorder in which a single nucleotide change in the β-globin gene causes hemoglobin to aggregate, changing the red blood cell shape and causing multiple symptoms in afflicted individuals

a human genetic disease caused by a recessive allele for a dysfunctional enzyme, leading to accumulation of certain lipids in the brain; seizures, baldness, and degeneration of motor and mental performance usually become manifest a few months after birth, followed by death with a few years

breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype; the ration of phenotypes in the offpsring reveals the unknown genotype

one of two or more detectable variants in a genetic character

referring to organisms that produce offspring of the same variety over many generations of self-pollination