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May 23, 2024 · Definition. Chromosomes are threadlike structures made of protein and a single molecule of DNA that serve to carry the genomic information from cell to cell. In plants and animals (including humans), chromosomes reside in the nucleus of cells. Humans have 22 pairs of numbered chromosomes (autosomes) and one pair of sex chromosomes (XX or XY ...
May 23, 2024 · Definition. A plasmid is a small circular DNA molecule found in bacteria and some other microscopic organisms. Plasmids are physically separate from chromosomal DNA and replicate independently. They typically have a small number of genes — notably, some associated with antibiotic resistance — and can be passed from one cell to another.
May 21, 2024 · An allele is a term coined to describe a specific copy of a gene. Genes, the DNA sequences controlling our traits, are usually found in two copies in eukaryotic genomes; each copy (allele) is inherited from one parent. Each allele occupies a specific region on the chromosome called a gene locus. The gene’s two alleles are located in the same ...
May 23, 2024 · Definition. An allele is one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location. An individual inherits two alleles, one from each parent, for any given genomic location where such variation exists. If the two alleles are the same, the individual is homozygous for that allele. If the ...
May 23, 2024 · Locus. Locus is a term that we use to tell us where on a chromosome a specific gene is. So it's really the physical location of a gene on a chromosome. It's a way of defining the gene's neighborhood. If you consider the entire chromosome as a country where the gene is found, and then a region of the chromosome would be the city.
May 23, 2024 · Definition. A mutagen is a chemical or physical agent capable of inducing changes in DNA called mutations. Examples of mutagens include tobacco products, radioactive substances, x-rays, ultraviolet radiation and a wide variety of chemicals. Exposure to a mutagen can produce DNA mutations that cause or contribute to certain diseases.
May 21, 2024 · Definition. A single nucleotide polymorphism (abbreviated SNP, pronounced snip) is a genomic variant at a single base position in the DNA. Scientists study if and how SNPs in a genome influence health, disease, drug response and other traits.
