Genetics — Genome Characteristics

Notecards from the first reading "Genome Characteristics"

Genome

A single copy of a heritable genetic material of a virus, bacterium, archaean, protist, fungus, plant, or animal.

Genome Cartography

Mapping a genome

Endosymbiont

An organism that lives within or on another organism.

Eukaryote

An organism with a eukaryotic cell type that maps to the

Domain Eukaryota

Kingdoms: Protista (protists), Fungi, Plantae (plants), and

Animalia (animals)

(Membrane bound nucleus)

Eukaryotic Genome

The heritable genetic material of an eukaryote.

Chloroplast DNA (Chloroplast Genome)

Heritable double-stranded DNA in a chloroplast, an organelle where photosynthesis occurs.

Only photosynthetic protists and plants.

…

Chromid

Medium-sized (subjective) double-stranded DNA (dsDNA) found in some bacteria, mitochondria, and chloroplasts.

Circular and Linear; ALWAYS dsDNA

Chromosome

Complex of large (subjective) double-stranded DNA (dsDNA) and proteins.

Describe large, heritable double-stranded DNAs that encode essential genes.

Circular or Linear; ALWAYS double stranded

Circular nucleic acid

Nucleic acid with a circle-like appearance—a molecule with no recognizable ends.

ssRNAs, dsRNAs, ssDNAs, dsDNAs

ss

Single Stranded

ds

Double Stranded

Deoxyribonucleotide (dNTP)

A kind of nucleotide that makes up DNA.

Pentose sugar deoxyribose (sugar), Phosphate group, Nitrogenous

bases: adenine (A), thymine (T), guanine (G), and cytosine (C).

Note: Ribonucleotides also have adenine, guanine, and cytosine but have uracil (U) in place of thymine.

DNA (deoxyribonucleic acid)

Type of nucleic acid made up of deoxyribonucleotides joined

together in a specific sequence

Either ss or ds; circular or linear

Primary function is a repository of genetic information passed from parent cells to daughter cells and from parents to offspring.

Double-stranded (ds) nucleic acid

A nucleic acid composed of two strands.

Physically held together by hydrogen bonding between complementary nitrogenous bases

One molecule, even though both strands are themselves molecules.

Can be ds; dsDNA, dsRNA

Extrachromosomal DNA

Describe heritable double-stranded DNA that is not considered nuclear DNA, mitochondrial DNA, or chloroplast DNA. Can be in the nucleus, cytosol, or outside of the cell.

Now considered by some to be one of the four components of a eukaryotic genome.

non-segmented and linear double-stranded DNA (dsDNA), non-segmented and circular double-stranded DNA (dsDNA), segmented and linear double-stranded DNA (dsDNA), segmented and circular double-stranded DNA (dsDNA), segmented linear and circular double-stranded DNA (dsDNA)

Form (genome)

The physical structure or shape of the nucleic acid(s) that make up a genome (nucleic acid can be linear or circular, DNA or RNA, ds or ss; genomes can be composed of either nucleic acid or both)

Genetic material

Nucleic acids that are repositories of information

Genome length

Measure of genome size that is reported in bases (ss na) or base pairs (ds na) and is a measure of how many nucleotides are in a strand. Large including bp, kb or kbp, mb or map, gb or gbp

bp

base pair

kb or kip

kilobase or kilobase pair

1,000 bp or 103 bp

mb or mbp

Megabase or Megabase pairs

1,000,000 bp or 106 bp

gb or gbp

Gigabase or Gigabase pairs

1,000,000,000 bp or 109 bp

Genome mass

A measure of genome size reported in picograms (pg) and is a reflection of how many nucleotides are in a genome.

Heritable

Capable of being passed from parent to offspring

Syn: inheritance (inherit) or transmission (transmit)

Linear nucleic acid

A nucleic acid with a line-like appearance—a molecule with two recognizable ends.

Can be ssRNAs, dsRNAs, ssDNAs, dsDNAs.

Mini-chromosome

A medium-sized (relative) double-stranded DNA (dsDNA) found in some archaea.

Encode essential genes, like chromosomes, and use the same replication and segregation machinery as chromosomes.

Can be circular or linear, but ALWAYS dsDNA.

Mitochondrial DNA (a.k.a. mitochondrial genome)

Heritable double-stranded DNA in a mitochondrion, an organelle where portions of cellular respiration occur. Most, but not all, eukaryotes have mitochondria.

Very similar characteristics to bacterial genomes. Mitochondria contain chromosome(s), and sometimes chromid(s) and/or plasmid(s).

non-segmented and linear double-stranded DNA (dsDNA), non-segmented and circular double-stranded DNA (dsDNA), segmented and linear double-stranded DNA (dsDNA), segmented and circular double-stranded DNA (dsDNA), segmented and linear and circular double-stranded DNA (dsDNA)

Non-segmented genome