Chapter 9

the science of heredity

a heritable feature that varies among individuals in a population. such as flower color in pea plants

a variant of a character. such as purple or white flowes

the fusion of sperm and egg produced by the same individual organism

the fusion of sperm and egg derived from two different individuals

self fertilization produced offspring all identical to the parent

the offspring of parents of two different species or of two different varieties of one species; the offspring of two parents that differ in one or more inherited traits; an individual that is heterozygous for one or more pairs of genes

a mating of two sexually reproducing individuals, often used to describe a genetics experiment involving controlled mating

the true-breeding parental plants.(P for parental)

the hybrid offspring of the P generation. (F for filial, "son")

when F₁ plants self-fertilize or fertilize each other

the parental plants differ in only one character

an alternative version of a gene

an organism that has two identical alleles for a gene

an organism that has two different alleles for a gene

the allele that determines the organisms appearance

the allele that has no noticeable effect on the organisms appearance

rule in inheritance that individuals have two alleles for each gene and that when gametes form by meiosis, the two alleles separate, each gamete resulting with only one allele of each gene;also known as first law of inheritance

shows the four possible combinations of gametes; shows the results of random fertilization

an organisms genetic makeup

an organisms expressed, or physical, traits

an experimental mating of individuals at two genetic loci

each pair of alleles segregates independently of other pairs of alleles during gamete formation

states that the probability of a compound event is the product of separate probabilities of the independent events

states that the probability that an event can occur in two or more alternative ways is the sum of the separate probabilities of the different ways

a family tree representing the occurrence of heritable traits in parents and offspring across a number of generations

an individual who is heterozygous to a recessively inherited disorder and therefore does not show symptoms of the disorder but who may pass on the recessive allele to offspring

a fatal genetic disease in the U.S. a person who has two copies of the allele has cystic fibrosis, which is characterized by an excessive secretion of very thick mucus from the lungs, pancreas, and other organs

a mating of close relatives that is more likely to produce offspring homozygous for recessive traits

a dominant disorder that is a form of dwarfism

a degenerative disorder of the nervous system that usually does not appear until 35-45 years of age.

a test for a genetic disorder for an unborn child.

a procedure performed to test for a genetic disorder

a test used to find anatomical deformities that uses sound waves to produce a picture

a type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable

a type of inheritance in which the phenotype of a heterozygote (Aa) is intermediate between the phenotypes of the two types of homozygotes (AA and aa)

involves three alleles of a single gene. These three alleles, in various combinations, produce four phenotypes: a person's blood type may be either O,A,B, or AB

inheritance pattern in which he heterozygote expresses the distinct trait of both alleles

the control of more than one phenotypic characteristic by a single gene

the additive effects of two or more genes on a single phenotypic character

stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns

genes located close together on the same chromosome tend to be inherited together

the percentage of recombinants

a chromosome that determines whether an organism is male or female using X and y

a gene located on either sex chromosome

a sex-linked recessive trait with a long, well documented history. lacking one or more of the proteins required for blood clotting

a recessive sex-linked disorder that is a malfunction of light-sensitive cells in the eyes

a sex-linked recessive disorder that has a condition characterized by a progressive weakening of the muscles and loss of coordination