Year: 2022

EQUALLY, when Craig Venter's team created "the minimal cell" in 2016, with only 473 genes, a large number of these genes "essential for life" have functions that are "yet to be determined". https://lnkd.in/e9ZJKP5 View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend with the issue of the species barrier. While it can be argued that in the light of evolutionary timeframes, species are not fixed, and by definition, evolve; nevertheless, in smaller time windows, successful species interbreeding is limited, and controlled by specific genes. View in LinkedIn

INTERBREEDING between distinct species. Canines such as wolves, coyotes and dogs (different species) can successfully reproduce. Biological isolation of species is not the same as the inability to produce fertile offspring. Reproductive isolation can be geographic, genetic or behavioral. Rather, "if two species cannot interbreed, they are not the same species." https://lnkd.in/eP7ybxR View in LinkedIn

PROBLEMS OF INBREEDING between genetically closely related individuals of the same species. Increased susceptibility to diseases, resulting from diminished genetic variability (heterozygosity), is a consequence of inbreeding between a single species. Deleterious recessive alleles are propagated and the breed looses 'vigor'. Inbreeding however is common in some parasites and aggressive weeds where purging by selection filters the gene pool. https://lnkd.in/eCqEHEc View in LinkedIn

"GENETIC DIVERSITY is the total number of genetic characteristics in the genetic makeup of a species. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals." https://lnkd.in/ek-X-q4 View in LinkedIn

SPECIES BARRIERS. "The definition of a species is that it cannot breed successfully with another species, so "to understand speciation is to understand how these reproductive barriers evolved...You call them new species when there are barriers that prevent them from breeding with each other. Identifying these genes and uncovering the molecular basis of hybrid sterility or death is key to understanding how new species evolve and remains one of the big and longstanding questions in biology since Darwin." https://lnkd.in/euTejtt View in LinkedIn

CROSSING THE SPECIES BARRIER. "Though the transfer of viruses between different host species is rare, those that do cross the species barrier often lead to severe outbreaks; further adaptation can then result in the emergence of variants worldwide. For a virus to cross between species, several genetic adaptations need to occur in the virus." https://lnkd.in/eRYaKeC View in LinkedIn

HOST RANGE. "Many infectious diseases cross the species barrier. Generally, this crossing occurs either because humans come into contact with a microorganism that is already capable of causing human infection or because an alteration occurs in the spectrum of species for which the organism is pathogenic — the so-called host range." https://lnkd.in/enTxJtp View in LinkedIn

POLYPLOIDY LEADS TO HYBRIDS. "In plants, new, reproductively isolated species may arise instantaneously, due to multiplication of the entire complement of chromosomes by a process known as polyploidy. This may occur as a result of hybridization, combining the chromosome sets from two parent species in a hybrid individual. If such hybrids turn out to be well adapted to environmental conditions, hybridization is a mechanism that produces new species." https://lnkd.in/ejwXt8N View in LinkedIn

PLANT VEGETATIVE REPRODUCTION. "Even if hybrids are unable to undergo sexual reproduction because their chromosomes do not sort out properly in meiosis, they may reproduce vegetatively." https://lnkd.in/ejwXt8N View in LinkedIn