Organisms have all genetic material in chromosomes {genome, genetics}|. Typical animal cells express 4,000 to 10,000 genes. Humans have more than 30,000 genes. Two unrelated people differ in 100 to 5000 genes. Human genes differ from chimpanzee genes by one percent. Humans have 85,000 different mRNAs.
Transposable elements are 45% of human DNA. Non-coding DNA is 24% of human DNA. Structural DNA is 20% of human DNA. Repeated sequences are 10% of human DNA.
Protein coding genes are 1% of human DNA. 42% of genes have not been characterized. 14% are nuclear transcription factors. 12% are messengers. 10% are enzymes. 5% are miscellaneous. 5% are structural. 5% are for molecular transport. 3% are cell-surface proteins. 3% are tumor-suppressor genes. 1% are immune-system proteins.
People have 5 x 10^9 nucleotides. Unrelated people differ by 5 x 10^5 nucleotides.
Genes have sequences, functions, regulation, and interactions with themselves and environment {genomics}|. Computational tools can identify genes, inducers, binding sites, structures, and relations between nucleic acid and protein sequences.
Protein study can depend on genes {proteomics}|. Proteomics involves post-translational modification, protein folding, and protein-protein interactions. 10 to 20 million different human proteins are possible.
Human bacteria and humans make many chemicals {metabolomics}. Human bacteria and humans make many chemicals in response to stress {metabonomics}.
Projects {genome, human} {Human Genome Project} sequenced human DNA.
purposes
From nucleotide sequences, experimenters can determine gene number, types, and relations. They can identify functional regions, coding regions, pseudogenes, and loci. They can identify regulatory regions, such as promoters, enhancers, silencers, trans-activating factors, transcription factors, and transcription-factor receptors. They can identify splicing sites, such as RNA splicing sites and alternative splicing sites. They can identify repeat regions, such as simple repeats like STR, complex repeats like Alu, or coding-triplet repeats. They can identify translocations and DNA-rearrangement signals. They can identify three-dimensional structure sites. They can identify antigen response sites. They can identify sites involved in polymorphism, disease, and development.
evolution
Experimenters can find racial, cultural, geographic, and individual variations. They can identify evolutionary regions, such as orthologues or dot matrices. They can trace human DNA evolution. They can define heredity traits and study questions about environment role {nature vs. nurture debate}.
questions
Should fetal tissues be research tools?
Should society allow changes to germ cells? How much diversity should society maintain and how much should society try for perfection? Which eugenics program is best, if any? Do parents have right to choose children gender?
Who owns information about genes, regions, or proteins, and is it patentable? Who owns genetic materials and data?
Who can access genetic information: relatives, governments, insurance, and/or employers? How can people have privacy?
Should gene therapies modify behavior? Should society screen everyone for genetic diseases or traits? Is it ethical to have disease diagnosis without available treatment? Should society allow children to have genetic defects, and what are defects? Are treatment costs important factors?
Is anyone liable for genetic makeup or behavior consequences? Does or will genetic defects cause social stigma?
How much education about genetic issues is practical and/or useful?
Genomes have numbers of homologous somatic chromosomes {ploidy}, such as haploid and diploid. Triploid organisms have three. Tetraploid organisms have four. For sex-linked chromosomes, ploidy can differ between males and females.
Cells {haploid}| can have one chromosome set, rather than two. Sperm and egg cells {germ cell} are haploid. Bacteria have one gene copy, because they are asexual. However, they have as many different traits and trait variations as sexual organisms.
Somatic cells {diploid}| can have two chromosome sets. Sexual reproduction contributes one chromosome set from each parent.
Many organisms have more than two chromosome sets {polyploidy}|. Haploids and diploids can make extra chromosomes or chromosome parts. Insects typically have more than two chromosome sets.
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Date Modified: 2022.0225