Ch 3 Book Terms Flashcards
primary RNA transcript (pre-mRNA)
The initial product of transcription that consists of an RNA extending from the promoter to the terminator and possesses the original 3′ and 5′ ends.
mature transcript
A modified RNA transcript. Modification may include the removal of intron sequences and alterations to the 5′ and 3′ ends.
interrupted gene
A gene in which the coding sequence is not continuous due to the presence of introns.
RNA splicing
The process of excising introns from RNA and connecting the exons into a continuous mRNA.
complementary DNA (cDNA)
The double-stranded DNA that is synthesized from a single- stranded RNA template through a reaction catalyzed by reverse transcriptase.
paralogous genes (paralogs)
Genes that share a common ancestry due to gene duplication.
overlapping gene
A gene in which part of the sequence is found within part of the sequence of another gene.
alternative splicing
The production of different RNA products from a single product by changes in the usage of splicing junctions.
gene family
A set of genes within a genome that code for related or identical proteins or RNAs. The members were derived by duplication of an ancestral gene followed by accumulation of changes in sequence between the copies. Most often the members are related but not identical.
superfamily
A set of genes all related by presumed descent from a common ancestor but now showing considerable variation.
orthologous genes (orthologs)
Related genes in different species.
homologous genes (homologs)
Related genes in the same species, such as alleles on homologous chromosomes or multiple genes in the same genome sharing common ancestry.
purine-loading (AG) pressure
The tendency of a species’ AG (purine) content at the first, second, and third positions of the codons of its genes to conform to an optimal value.
GC pressure
The tendency of a species’ genome to conform to its optimal GC content.
positional information
The localization of certain cell structures in specific places.
