artificial cross-fertilization
A controlled cross between plans made by an investigator who transfers pollen from one plant to fertilize the other
Controlled genetic cross
Genetic crosses controlled by an investigator who usually knows the genotype's and/or phenotypes of the organisms being crossed
Pure breeding strains
A group of genetically identical homozygous organisms that, when self crossed or intercrossed, only produce offspring that have a phenotype identical to the parents. Also as true breeding
Parental generation (P generation)
The parents of Avenue progeny. And control genetic crosses, the parents are pure breeding
F1 generation (first fillal generation)
The first generation of offspring. In genetic experiments, usually the offspring produced by crossing pure breeding parents.
F2 generation
The second generation, produced by crossing F1 organisms
F3 generation
The third generation, produced by crossing F2 organisms
replicate crosses
Repeated crosses involving parents with the same genotypes and phenotypes
reciprocal crosses
crosses in which the same genotypes are crossed but the sexes of donating parents are switched.
test cross
The cross of an organism with the dominant phenotype that may be heterozygous with an organism that is homozygous for a recessive allele. Also known as test cross analysis.
dominant phenotype
The phenotype observed in a heterozygous organism that is identical to the phenotype observed in a homozygote. The phenotype produced when an organism is homozygous for the dominant allele or carries a single copy of the dominant allele in the heterozygou
recessive phenotype
The phenotype observed in an organism that is homozygous for the recessive allele.
particulate inheritance
Mendel's theory that genetic information is transmitted from one generation to the next as discrete units or elements of heredity.
Mendel's theory which proposes that each plant carries two particles of heredity for each trait. A plant receives one unit o
monohybrid cross
a cross between two organisms that have the same heterozygous genotype for one gene.
phenotypic ratio (3:1 and 9:3:3:1 ratio)
A ratio or set of relative proportions between organisms with different phenotypes - e.g., The ratio of progeny produced by a monohybrid cross (3:1) or a dihybrid cross (9:3:3:1)
genotypic ration (1:2:1 ratio)
(1) A ratio or set of relative proportions between organisms with different genotypes. (2) The ratio of 1/4: 1/2: 1/4 observed among the homozygous and heterozygous F2 progeny of a monohybrid cross.
gametes
The reproductive cells produced by male and female reproductive structures sperm or pollen in male animals and plants, and eggs in females.
Law of segregation, Mendel's first law
The separation of alleles of a gene during gamete formation.
dihybrid cross
A cross between organisms that are heterozygous for two loci
Law of independent assortment, Mendel's second law
During gamete formation, the segregation of alleles at one locus is independent of the segregation of alleles at another locus.
trihybrid cross
A genetic cross between organisms that are heterozygous for three genes
product rule
The probability of an event requiring the sequential or simultaneous occurrence of two or more contributing events. The probabilities of contributing events are multiplied and their product is the event in question. Also known as the multiplication rule.
addition rule
the joint probabilityof occurrence of any two or more mutually exclusive events by summing the probabilities of each event.
Pascal's triangle
A diagram listing the coefficients of a given binomial expansion in which the binomial expression is the expanded n number of times
Normal (Gaussian) distribution
The continuous distribution of outcomes predicted by chance.
standard deviation
A statistical value that measures the scatter of outcome values around the average outcome value. Expressed as the square toot of the sum of squared deviations of each value from the mean value.
autosomal inheritance
Hereditary transmission of genes carried on autosomes.
autosomal dominant inheritance
A pattern of heredity transmission in which the dominant allele of an autosomal gene results in the appearance of the dominant phenotype.
autosomal recessive inheritance
A pattern of heredity transmission in which the recessive allele of an autosomal gene results in the appearance of the recessive phenotype
6 characteristics of autosomal dominant inheritance
1. Each individual who has the disease has at least one affected parent.
2. Males and females are affected in equal numbers
3. Either sex can transmit the disease allele
4. In crosses in which one parent is affected and the other is not, approx half of of
6 characteristics of autosomal recessive inheritance
1. Individuals who have the disease are often born to parent who do not.
2. If only one parent has the disorder, the risk that a child has the disorder depends on the genotype of the other parent.
3. If both parents have the disorder, all children will ha
Several features of Gregor Mendel's experiments on plant breeding and patterns of inheritance distinguished his work from that of his contemporaries. Which of the following was a critical experimental innovation employed by Mendel that distinguished his e
Mendel performed controlled crosses with pure-breeding strains.
Many of Mendel's experiments involved crosses in which the sexes of the pure-breeding parents were switched. In each case he observed an F1 with the same phenotype. These pairs of experimental crosses are known as _______.
reciprocal crosses
Mendel's law of segregation predicts the following specific phenotypic ratios among the F1 and F2 progeny from crosses between two pure-breeding parents for a single trait (e.g., yellow vs. green peas).
F1 1:0 F2 3:1 - A monohybrid cross for a dichotomous trait always yields a single phenotype (the dominant trait) in the F1 and a 3:1 phenotype ratio (3 dominant : 1 recessive) in the F2.
Experimental support for Mendel's law of segregation comes from the results of self-fertilizing F2 plants that display the dominant phenotype. Based on the law of segregation, what proportion of the dominant F2 plants would be expected to produce F3 proge
2/3 - Of the F2 progeny that display the dominant phenotype, 2/3 are heterozygous. Their progeny (F3) will display 3:1 phenotype ratios.
Based on Mendel's law of independent assortment, what phenotypic ratios are expected among the F2 progeny from a dihybrid cross such as the one illustrated in figure above?
9:3:3:1 - Most progeny, 9/16, are expected to display the dominant phenotype for both traits, 3/16 are expected to display the dominant phenotype for the first trait and the recessive phenotype for the second trait, 3/16 are expected to display the recess
How many different combinations of alleles are possible among the gametes produced by an individual that is heterozygous for three separate genes?
Eight
Imagine a couple that is ready to start a family. They plan to have exactly four children. Assuming no multiple births (twins, triplets, etc.), use the information provided in Pascal's triangle (in figure above) to determine how many different ways they m
Four
p values for chi-square tests provide a quantitative measure of the probability that the results of another replicate experiment will deviate as much or more from expected results by chance. By convention, the chance hypothesis is rejected when the p valu
0.05
In pedigree analysis, which of the following is a hallmark of an autosomal recessive disorder?
Individuals who have the disease are commonly born to normal (unaffected) parents.
Two unaffected parents will not have any children with the disease.
Two affec
Individuals who have the disease are commonly born to normal (unaffected) parents.
The wrinkled seed phenotype used by Mendel results from a defect in the gene that encodes which of the following products?
Starch-branching enzyme - The loss of function of the starch-branching enzyme results in excess sugar molecules, which causes retention of water in the developing seed. The extra water is lost as the seeds mature. This dehydration causes the seeds to part