The current record holder is the gene Dscam in Drosophila. Alternative splicing of its 95 exons could potentially produce more than 38,000 kinds of proteins from this single gene.

TLS Online TPP Program

#Id: 9186

#Section 3: Genetics, Cellular and Molecular Biology

Relative genotypic frequency after selection

TLS Online TPP Program

#Id: 9187

#Section 3: Genetics, Cellular and Molecular Biology

Positive Selection: The Spread of Beneficial Mutations

TLS Online TPP Program

#Id: 9188

#Section 3: Genetics, Cellular and Molecular Biology

There are three basic modes of selection on a quantitative trait.

TLS Online TPP Program

#Id: 9189

#Section 3: Genetics, Cellular and Molecular Biology

Overdominance the heterozygote has higher fitness than the  fitnesses of the two homozygotes

Underdominance, in which the heterozygote has lower fitness than both homozygotes.

Directional selection leads to fixation of the favored allele and elimination of the other allele, as  long as no other evolutionary forces act on the population.

TLS Online TPP Program

#Id: 9190

#Section 3: Genetics, Cellular and Molecular Biology

Artificial selection- Genetically improving animals and plants by breeding together the best individuals in their fields and flocks.

TLS Online TPP Program

#Id: 9191

#Section 3: Genetics, Cellular and Molecular Biology

Types of selection