AlleleAn allele (UK: ) is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. Alleles can differ at a single position through single-nucleotide polymorphisms, but they can also have insertions and deletions of up to several thousand base pairs.
Homologous chromosomeHomologous chromosomes or homologs are a set of one maternal and one paternal chromosome that pair up with each other inside a cell during meiosis. Homologs have the same genes in the same loci but possibly different alleles, where they provide points along each chromosome that enable a pair of chromosomes to align correctly with each other before separating during meiosis.
PloidyPloidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomalgenes. Here sets of chromosomes refers to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair—the form in which chromosomes naturally exist.
Locus (genetics)In genetics, a locus (pl.: loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located. Each chromosome carries many genes, with each gene occupying a different position or locus; in humans, the total number of protein-coding genes in a complete haploid set of 23 chromosomes is estimated at 19,000–20,000. Genes may possess multiple variants known as alleles, and an allele may also be said to reside at a particular locus.
Genetic disorderA genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome.
Sex-determination systemA sex-determination system is a biological system that determines the development of the organism's sex. Most organisms that create their offspring using sexual reproduction have two common sexes, males and females, and in other species there are hermaphrodites, organisms that can function reproductively as either female or male, or both. There are also some species in which only one sex is present, temporarily or permanently.
ChromosomeDNA molecule containing genetic material of a cellDifferent representations of chromosomesMain parts of a condensed chromosomeCondensed chromosome (purple rod) inside a bone marrow erythrokaryocyte undergoing mitosisDiagram of a duplicated and condensed metaphase eukaryotic chromosome: ChromatidCentromereShort armLong armA chromosome is a package of DNA containing part or all of the genetic material of an organism.
GeneIn biology, the word gene has two meanings. The Mendelian gene is a basic unit of . The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce RNA. There are two types of molecular genes: protein-coding genes and non-coding genes. During gene expression (the synthesis of RNA or protein from a gene), DNA is first copied into RNA. RNA can be directly functional or be the intermediate template for the synthesis of a protein.
ZygoteA zygote ( from Ancient Greekζυγωτός (zygōtós)'joined, yoked', from ζυγοῦν (zygoun)'to join, to yoke') is a eukaryoticcell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism.
EukaryoteDomain of life whose cells have nucleiThe eukaryotes () are cellularorganisms of the domainEukaryota or Eukarya, which have a distinct cell nucleus (formed by a nuclear membrane), membrane-bound organelles and organization supported by a cytoskeleton. Extant eukaryotes are traditionally grouped into four kingdoms: animals, plants, fungi and protists.
Homologous chromosomeHomologous chromosomes or homologs are a set of one maternal and one paternal chromosome that pair up with each other inside a cell during meiosis. Homologs have the same genes in the same loci but possibly different alleles, where they provide points along each chromosome that enable a pair of chromosomes to align correctly with each other before separating during meiosis.PloidyPloidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomalgenes. Here sets of chromosomes refers to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair—the form in which chromosomes naturally exist.Locus (genetics)In genetics, a locus (pl.: loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located. Each chromosome carries many genes, with each gene occupying a different position or locus; in humans, the total number of protein-coding genes in a complete haploid set of 23 chromosomes is estimated at 19,000–20,000. Genes may possess multiple variants known as alleles, and an allele may also be said to reside at a particular locus.Genetic disorderA genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome.Sex-determination systemA sex-determination system is a biological system that determines the development of the organism's sex. Most organisms that create their offspring using sexual reproduction have two common sexes, males and females, and in other species there are hermaphrodites, organisms that can function reproductively as either female or male, or both. There are also some species in which only one sex is present, temporarily or permanently.ChromosomeDNA molecule containing genetic material of a cellDifferent representations of chromosomesMain parts of a condensed chromosomeCondensed chromosome (purple rod) inside a bone marrow erythrokaryocyte undergoing mitosisDiagram of a duplicated and condensed metaphase eukaryotic chromosome: ChromatidCentromereShort armLong armA chromosome is a package of DNA containing part or all of the genetic material of an organism.GeneIn biology, the word gene has two meanings. The Mendelian gene is a basic unit of . The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce RNA. There are two types of molecular genes: protein-coding genes and non-coding genes. During gene expression (the synthesis of RNA or protein from a gene), DNA is first copied into RNA. RNA can be directly functional or be the intermediate template for the synthesis of a protein.ZygoteA zygote ( from Ancient Greekζυγωτός (zygōtós)'joined, yoked', from ζυγοῦν (zygoun)'to join, to yoke') is a eukaryoticcell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism.EukaryoteDomain of life whose cells have nucleiThe eukaryotes () are cellularorganisms of the domainEukaryota or Eukarya, which have a distinct cell nucleus (formed by a nuclear membrane), membrane-bound organelles and organization supported by a cytoskeleton. Extant eukaryotes are traditionally grouped into four kingdoms: animals, plants, fungi and protists.*As an Amazon Associate I earn from qualifying purchases.