Chimerism | Incomplete dominance | Codominance | Recombination

A genetic chimerism or chimera is a single organism composed of cells with more than one distinct genotype. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood types, subtle variations in form (phenotype) and, if the zygotes were of differing sexes, then even the possession of both female and male sex organs (this is just one of many different phenomena that may result in intersex conditions). Animal chimeras are produced by the merger of two (or more) embryos. In plant chimeras, however, the distinct types of tissue may originate from the same zygote, and the difference is often due to mutation during ordinary cell division. Normally, genetic chimerism is not visible on casual inspection; however, it has been detected in the course of proving parentage. Another way that chimerism can occur in animals is by organ transplantation, giving one individual tissues that developed from a different genome. For example, transplantation of bone marrow often determines the recipient’s ensuing blood type. What is Incomplete Dominance? Incomplete dominance is a form of Gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype. It is also known as partial dominance. For eg., in roses, the allele for red colour is dominant over the allele for white colour. But, the heterozygous flowers with both the alleles are pink in colour. Incomplete Dominance and Codominance Incomplete dominance and codominance are different from each other. In codominance, both the alleles present on a gene are expressed in the phenotype. A flower showing codominance will have patches of red and white instead of a uniformly pink flower. In incomplete dominance, the F2 generation from heterozygous plants will have a ratio of 1:2:1 with the phenotypes red, white and spotted flowers. The humans with AB blood type also show codominance where the alleles for both blood types A and B are expressed. Problem: A gene for corn has two alleles, one for yellow kernels and one for white kernels. Cross pollination of yellow corn and white corn results in ears of corn that have an approximately even mix of yellow and white kernels. Which term best describes the relationship between the two alleles? A) Genetic recombination B) Codominance C) Incomplete dominance D) Chimerism #punnettSquares #codominance #Genetics #epistasis #IncompleteDominance #polygenic #traits #Genes #Dominant #recessive #Phenotype #highSchoolBiology #nonmendelianTraits #NikolaysGeneticsLessons #dominanceAndItsTypes #typesOfDominanceInGenetics #geneticsDon39tMemorise #geneticsBasics #geneticsClass10Icse #dominance #typesOfDominance #completeDominance #mendelianExperimentPeaPlant #basicsOfGenetics #geneticsAndEvolution