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The term monophyly, or monophyletic, derives from the two Ancient Greek words μόνος (mónos), meaning "alone, only, unique", and φῦλον (phûlon), meaning "genus, species", [4] [5] and refers to the fact that a monophyletic group includes organisms (e.g., genera, species) consisting of all the descendants of a unique common ancestor.
Horizontal gene transfer is the mobility of genetic info between different organisms that can have immediate or delayed effects for the reciprocal host. [46] There are several processes in nature which can cause horizontal gene transfer. This does typically not directly interfere with ancestry of the organism, but can complicate the ...
Other examples of polyphyletic groups are algae, C4 photosynthetic plants, [4] and edentates. [5] Many taxonomists aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes.
In biological phylogenetics, a clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as a monophyletic group or natural group, [1] is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. [2]
The term paraphyly, or paraphyletic, derives from the two Ancient Greek words παρά (pará), meaning "beside, near", and φῦλον (phûlon), meaning "genus, species", [2] [3] and refers to the situation in which one or several monophyletic subgroups of organisms (e.g., genera, species) are left apart from all other descendants of a unique common ancestor.
Gene structure is the organisation of specialised sequence elements within a gene. Genes contain most of the information necessary for living cells to survive and reproduce. [ 1 ] [ 2 ] In most organisms, genes are made of DNA, where the particular DNA sequence determines the function of the gene.
Paragroup is a term used in population genetics to describe lineages within a haplogroup that are not defined by any additional unique markers.. In human Y-chromosome DNA haplogroups, paragroups are typically represented by an asterisk (*) placed after the main haplogroup.
Double-stranded DNA is coiled around histones that play an important role in regulating gene expression so the replicated DNA must be coiled around histones at the same places as the original DNA. [44] To ensure this, histone chaperones disassemble the chromatin before it is replicated and replace the histones in the correct place. Some steps ...