Section 9-1 Review: Mendel's Legacy & Section 9-2 Review: Genetic Crosses
a genetic cross performed many times produces 798 long-stemmed plant in a similar cross is
266/1,064
A monohybrid cross of two individuals that are heterozygous for a trait exhibiting complete dominance would probably result in a phenotypic ratio of
3 dominant: 1 recessive
What does the term allele mean as it is used in genetic crosses
An allele is each of two alternate forms of a gene
F2 generation
F2 generation is the plants generated when F1 self pollinates
A cross between true-breeding green-podded pea plants and true-breeding yellow-podded pea plants produces only green-podded plants. When the F1 generation is allowed to self pollinate, the F2 generation consists of
about three-quarter green-podded plants and one-quarter yellow-podded plants
Mendel obtained plants that were true-breeding for particular traits by
allowing plants to self-pollinate for several generations
Dominant
dominant genes are the common genes
Recessive
genes which are not as common
To determine the genotype of an individual that shows the dominant phenotype, you would cross that individual with one that is
homozygous recessive
When alleles for different characteristics are on separate chromosomes, they are distributed to gametes independently. This observation is summarized by the law of
independent assortment
incomplete dominance
neither allele is more dominate than the other
codominance
occurs when both alleles for a gene are expressed in a heterozygous offspring
The appearance of an organism is its
phenotype
self-pollination
pollination of a flower by pollen from the same flower or from a flower on the same plant
cross-pollination
pollination of a flower with pollen from another flower
F1 generation
the first filial generation of offspring from p generation
when Mendel crossed a strain of tall pea plants with a strain of short pea plants, he observed that all of the plants in the F1 generation were tall. This suggests that
the tall trait was controlled by a dominant factor
Explain how the events of meiosis account for the law of segregation and the law of independent assortment
two alleles of each gene are segregated when the two chromosomes in each pair of homologues are separated into different gametes
Complete dominance
when one allele is completely dominate over another