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Homoploid means "at the same ploidy level", i.e. having the same number of homologous chromosomes. For example, homoploid hybridization is hybridization where the offspring have the same ploidy level as the two parental species. This contrasts with a common situation in plants where chromosome doubling accompanies or occurs soon after ...
Each level in the hierarchy represents an increase in organisational complexity, with each "object" being primarily composed of the previous level's basic unit. [2] The basic principle behind the organisation is the concept of emergence —the properties and functions found at a hierarchical level are not present and irrelevant at the lower levels.
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms.This number, along with the visual appearance of the chromosome, is known as the karyotype, [1] [2] [3] and can be found by looking at the chromosomes through a microscope.
Sugarcane can have ploidy levels higher than octaploid. [4] Polyploidization can be a mechanism of sympatric speciation because polyploids are usually unable to interbreed with their diploid ancestors. An example is the plant Erythranthe peregrina.
Comparative genomic hybridization (CGH) is a molecular cytogenetic method for analysing copy number variations (CNVs) relative to ploidy level in the DNA of a test sample compared to a reference sample, without the need for culturing cells.
Duplicated genes can be identified through sequence homology on the DNA or protein level. Paleopolyploidy can be identified as massive gene duplication at one time using a molecular clock . To distinguish between whole-genome duplication and a collection of (more common) single gene duplication events, the following rules are often applied:
A polyploid complex, also called a diploid-polyploid complex, is a group of interrelated and interbreeding species that also have differing levels of ploidy that can allow interbreeding. A polyploid complex was described by E. B. Babcock and G. Ledyard Stebbins in their 1938 monograph The American Species of Crepis : their interrelationships ...
A comparison of the genomic organization of six major model organisms shows size expansion with the increase of complexity of the organism. There is a more than the 300-fold difference between the genome sizes of yeast and mammals , but only a modest 4- to 5-fold increase in overall gene number (see the figure on the right).