Search results
Results from the WOW.Com Content Network
Homologous sequences are paralogous if they were created by a duplication event within the genome. For gene duplication events, if a gene in an organism is duplicated, the two copies are paralogous. They can shape the structure of whole genomes and thus explain genome evolution to a large extent. Examples include the Homeobox genes in animals.
Human physiology. The male external genitalia include the penis and the scrotum. The female external genitalia include the clitoris, the labia, and the vestibule, which are collectively called the vulva. External genitalia vary widely in external appearance among different people. One difference between the glans penis and the glans clitoridis ...
Two major concepts of comparative anatomy are: Homologous structures - structures (body parts/anatomy) which are similar in different species because the species have common descent and have evolved, usually divergently, from a shared ancestor. They may or may not perform the same function. An example is the forelimb structure shared by cats ...
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a duplication event (paralogs), or else a horizontal (or lateral) gene ...
Homology (biology), any characteristic of biological organisms that is derived from a common ancestor. Sequence homology, biological homology between DNA, RNA, or protein sequences. Homologous chromosomes, chromosomes in a biological cell that pair up (synapse) during meiosis. Homologous recombination, genetic recombination in which nucleotide ...
The pattern of limb bones called pentadactyl limb is an example of homologous structures (Fig. 2e). It is found in all classes of tetrapods (i.e. from amphibians to mammals). It can even be traced back to the fins of certain fossil fishes from which the first amphibians evolved such as tiktaalik.
The most common form of chromosomal crossover is homologous recombination, where the two chromosomes involved share very similar sequences. Non-homologous recombination can be damaging to cells, as it can produce chromosomal translocations and genetic abnormalities.
Chromosomes are linear arrangements of condensed deoxyribonucleic acid (DNA) and histone proteins, which form a complex called chromatin. [2] Homologous chromosomes are made up of chromosome pairs of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci.