A common name (but used formally) for a group of organisms that are mostly kinds of algae including BACILLARIOPHYTA; OOMYCETES; PHAEOPHYCEAE; and CHRYSOPHYCEAE. They all contain CHLOROPLASTS that are thought to have been derived from the endosymbiosis of ancient RED ALGAE.

One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.

A group (or phylum) of unicellular EUKARYOTA (or algae) possessing CHLOROPLASTS and FLAGELLA.

Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.

The common name for the phylum of microscopic unicellular STRAMENOPILES. Most are aquatic, being found in fresh, brackish, and salt water. Diatoms are noted for the symmetry and sculpturing of their siliceous cell walls. They account for 40% of PHYTOPLANKTON, but not all diatoms are planktonic.

A division of predominantly marine EUKARYOTA, commonly known as brown algae, having CHROMATOPHORES containing carotenoid PIGMENTS, BIOLOGICAL. ALGINATES and phlorotannins occur widely in all major orders. They are considered the most highly evolved algae because of their well-developed multicellular organization and structural complexity.

Deoxyribonucleic acid that makes up the genetic material of algae.

The relationships of groups of organisms as reflected by their genetic makeup.

The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.

Community of tiny aquatic PLANTS and ANIMALS, and photosynthetic BACTERIA, that are either free-floating or suspended in the water, with little or no power of locomotion. They are divided into PHYTOPLANKTON and ZOOPLANKTON.

Self-replicating cytoplasmic organelles of plant and algal cells that contain pigments and may synthesize and accumulate various substances. PLASTID GENOMES are used in phylogenetic studies.

Cells of the higher organisms, containing a true nucleus bounded by a nuclear membrane.

The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.

A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.

DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.