50 terms

Campbell Biology Concepts and Connections Chapter 9

The Patterns of Inheritance
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genetics
the scientific study of heredity and hereditary variation
self-fertilize
the fusion of sperm and egg produced by the same individual organism
cross-fertilization
the fusion of sperm and egg derived from two different indivuals
true-breeding
referring to organisms to which sexual reproduction produces offspring with inherited traits identical to those of the parents
hybrids
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
P generation
the parent individuals from which offspring are derived in studies of inheritance
F1 generation
the first filial, or hybrid, offspring in a genetic cross-fertilization
F2 generation
offspring resulting from interbreeding of the hybrid F1 generation
monohybrid cross
an experimental mating of individuals differing in one genetic trait
allele
an alternative form of a gene; an example: A vs. a
homozygous
having two identical alleles for a given gene
heterozygous
having two different alleles for a given gene
law of segregation
A general rule in inheritance that individuals have two alleles for each gene and that when gametes form by meiosis, the two alleles separate, and each resulting gamete ends up with only one allele of each gene; also known as Mendel's first law of inheritance.
punnett square
a diagram used in the study of inheritance to show the results of random fertilization
phenotype
the expressed traits of an organism
genotype
the genetic makeup of an organism
dihybrid cross
an experimental mating of individuals differing at two genetic loci
law of independent assortment
a genetic rule in inheritance that when gametes form during meiosis, each pair of alleles for a particular characteristic segregate independently; also known as Mendel's second law of inheritance
testcross
the mating between an individual of unknown genotype for a particular characteristic and an individual that is homozygous recessive for that same characteristic
independent event
the outcome of any particular toss is unaffected by what has happened in previous attempts
compound event
the product of the separate probabilities of the independent events
rule of multiplication
a rule stating that the probability of a compound event is the product of the separate probabilities of the independent events
rule of addition
a rule stating 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
pedigree
a family tree representing the occurance of heritable traits in parents and offspring across a number of generations
carriers
an individual who is heterozygous for a recessively inherited disorder and does not show symptoms of that disorder
cystic fibrosis
a genetic disease that occurs in people with two copies of a certain recessive allele that causes heavy mucus production
inbreeding
a mating of close relatives
achondroplasia
a form of dwarfism
Huntington's disease
a degenerative disorder of the nervous system that usually does not begin until middle age
amniocentesis
physician carefully inserts a needle into uterus and extracts some amniotic fluid
chorionic villus sampling
physician carefully extracts sample of tissue from placenta
ultrasound imaging
uses sound waves to produce a picture
complete dominance
a type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable
incomplete dominance
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)
ABO blood group
genetically determined classes of human blood that are based on the presence or absence of carbohydrates A and B on the surface of red blood types A, B, AB, and O
pleiotropy
the control of more than one phenotypic characteristic by a single gene
polygenic inheritance
the additive effect of two or more gene loci on a single phenotypic characteristic
chromosome theory of inheritance
A basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.
linked genes
Genes located on the same chromosome that tend to be inherited together
recombination frequency
With respect to two given genes, the number of recombinant progeny from a mating divided by the total number of progeny. Recombinant progeny carry combinations of alleles different from those in either of the parents as a result of independent assortment of chromosomes or crossing over.
sex chromosome
A chromosome that determines whether an individual is male or female
sex linked gene
A gene located on a sex chromosome
red green color blindness
A category of common, sex-linked human disorders involving several genes on the X chromosome; characterized by a malfunction of light-sensitive cells in the eyes; affects mostly males but also homozygous females.
hemophilia
A human genetic disease caused by a sex-linked recessive allele; characterized by excessive bleeding following injury
Duchenne muscular dystrophy
A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue
XY Sex-determination system
Males are determined by an X and a Y chromosome; Females are determined by two X chromosomes
XO Sex-determination system
Males are determined by a lone X chromosome; Females are determined by two X chromosomes
ZW Sex-determination system
Males are determined by two Z chromosomes; Females are determined by a Z and a W chromosome
Chromosomal number Sex-determination system
Females are diploid and the males are haploid (also known as the haploid-diploid system of determination)
Mendel's 4 Postulates
1. We have alternate forms of genes that we now call allels.
2.We receive a maternal set and a paternal set of each gene.
3. Of any two alleles for a single gene that we received from each parent one will be dominant over the other (this only works in complete dominance traits).
4. Each gamete carries only one copy of an allele and are separated out independently and randomly (the law of segregation).