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Advantages of pea plants for genetic study
Many VarietiesMating can be controlledEach flower has sperm-producing(stamen) organs and egg...
plants that produce offspring of the samevariety when they self-pollinate
Mendel mated twocontrasting, true-breeding varieties, a processcalled________
The true-breeding parents are the_________
The hybrid offspring of the P generation are calledthe_____________
When F1 individuals self-pollinate or crosspollinatewith other F1 hybrids, the ____________is...
alternative versions of genes
Each gene resides at a specific ______ on aspecific chromosome
the two alleles for a heritable character separate(segregate) during gamete formation and end...
Law of segregation
a diagram for predicting the results of a genetic cross between individuals of known...
An organism with two identical alleles for acharacter is said to be________ for the gene controlling...
An organism that has two different alleles for agene is said to be __________ for the genecontrolling...
____________ are not true-breeding
GenotypeIn the example of flower color in pea plants, PPand Pp plants have the same phenotype...
How can we tell the genotype of an individual withthe dominant phenotype?
TestcrossThe answer is to carry out a testcross: breedingthe mystery individual with a homozygousrecessive...
individuals that are heterozygous for one character
Crossing two true-breeding parents differing in twocharacters produces __________
a cross between F1 dihybrids
states that each pair of alleles segregates independently of each other pair of alleles...
Law of independent assortment
Mendel’s laws of segregation and independentassortment reflect the rules of _______
The _____________ states that the probabilitythat two or more independent events will occurtogether...
Probability in an F1 monohybrid cross can bedetermined using__________
the multiplication rule
The ___________ states that the probability thatany one of two or more exclusive events willoccur...
The___________ can be used to figure out theprobability that an F2 plant from a monohybridcross...
rule of addition
A dihybrid or other multicharacter cross isequivalent to two or more independent____________...
In calculating the chances for various genotypes,each character is considered separately, andthen...
Inheritance of characters by a single gene maydeviate from simple Mendelian patterns in the...
– When alleles are not completely dominant orrecessive– When a gene has more than two alleles–...
___________occurs when phenotypesof the heterozygote and dominant homozygote areidentical
___________the phenotype of F1hybrids is somewhere between the phenotypes ofthe two parental...
In _____________, two dominant alleles affect thephenotype in separate, distinguishable ways
________ are simply variations in a gene’snucleotide sequence
For any character, dominance/recessivenessrelationships of alleles depend on the level atwhich...
a dysfunctional enzyme causes an accumulation of lipids in the brain
Most ______exist in populations in more than twoallelic forms
Most genes have multiple phenotypic effects, aproperty called______
PleiotropyFor example, pleiotropic alleles are responsible forthe multiple symptoms of certain...
in ______________a gene at one locus alters thephenotypic expression of a gene at a secondlocus
_______________are those that vary in thepopulation along a continuum
Quantitative variation usually indicates ___________, an additive effect of two or moregenes...
polygenic inheritanceSkin color in humans is an example of polygenicinheritance
The ______________ is the phenotypic rangeof a genotype influenced by the environment
norm of reactionFor example, hydrangea flowers of the samegenotype range from blue-violet to...
Norms of reaction are generally broadest forpolygenic characters, such characters are called...
An organism’s phenotype includes:
Physical appearanceInternal anatomyPhysiologybehavior
Why aren't humans good subjects for geneticresearch?
– Generation time is too long– Parents produce relatively few offspring– Breeding experiments...
Inheritance patterns of particular traits can betraced and described using _______________
Many genetic disorders are inherited in a __________ manner
___________are heterozygous individuals whocarry the recessive allele but are phenotypicallynormal
Recessively inherited disorders show up only inindividuals ____________ for the allele
_______________ (i.e., matingsbetween close relatives) increase the chanceof mating between...
____________ is the most common lethalgenetic disease in the United States
The disease is caused by the substitution of asingle amino acid in the hemoglobin protein inred...
Dominant alleles that cause a lethal diseaseare rare and arise by __________
In _________________, a sampleof the placenta is removed and tested
chorionic villus sampling (CVS)
In _____________, the liquid that bathes thefetus is removed and tested