Misplaced Pages

#766233

39-831: LZR may refer to: Lzr - a variant of the Stoned computer virus LZR ( Lempel - Ziv - Renau) - a lossless data compression algorithm LZR - the ICAO airline code for the Bulgarian airline Air Lazur LZR - the International Air Transport Association airport code for Lizard Island Airport in Australia LZR Racer - a high-end Speedo swimsuit Led Zeppelin Remasters -

78-546: A 1:2:1 genotype ratio with the first two classes showing the (A) phenotype, and the last showing the (a) phenotype, thereby producing the 3:1 phenotype ratio. Mendel did not use the terms gene, allele, phenotype, genotype, homozygote, and heterozygote, all of which were introduced later. He did introduce the notation of capital and lowercase letters for dominant and recessive alleles, respectively, still in use today. In 1928, British population geneticist Ronald Fisher proposed that dominance acted based on natural selection through

117-548: A compilation album of remastered material by rock group Led Zeppelin Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title LZR . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=LZR&oldid=855957078 " Category : Disambiguation pages Hidden categories: Short description

156-416: A given gene of any function; one allele can be dominant over a second allele of the same gene, recessive to a third, and co-dominant with a fourth. Additionally, one allele may be dominant for one trait but not others. Dominance differs from epistasis , the phenomenon of an allele of one gene masking the effect of alleles of a different gene. Gregor Johann Mendel , "The Father of Genetics", promulgated

195-453: A membrane-bound H antigen. The I enzyme adds a galactose. The i allele produces no modification. Thus the I and I alleles are each dominant to i ( I I and I i individuals both have type A blood, and I I and I i individuals both have type B blood), but I I individuals have both modifications on their blood cells and thus have type AB blood, so the I and I alleles are said to be co-dominant. Another example occurs at

234-406: A pink snapdragon flower. The pink snapdragon is the result of incomplete dominance. A similar type of incomplete dominance is found in the four o'clock plant wherein pink color is produced when true-bred parents of white and red flowers are crossed. In quantitative genetics , where phenotypes are measured and treated numerically, if a heterozygote's phenotype is exactly between (numerically) that of

273-668: Is a key concept in Mendelian inheritance and classical genetics . Letters and Punnett squares are used to demonstrate the principles of dominance in teaching, and the upper-case letters are used to denote dominant alleles and lower-case letters are used for recessive alleles. An often quoted example of dominance is the inheritance of seed shape in peas . Peas may be round, associated with allele R , or wrinkled, associated with allele r . In this case, three combinations of alleles (genotypes) are possible: RR , Rr , and rr . The RR ( homozygous ) individuals have round peas, and

312-402: Is different from Wikidata All article disambiguation pages All disambiguation pages Stoned (computer virus) A computer infected with the original version had a one in eight probability that the screen would declare: "Your PC is now Stoned!" , a phrase found in infected boot sectors of infected floppy disks and master boot records of infected hard disks , along with

351-410: Is moved to cylinder 0, head 0, sector 7. On floppy disks , the original boot sector is moved to cylinder 0, head 1, sector 3, which is the last directory sector on 360 kB disks. The virus will "safely" overwrite the boot sector if the root directory has no more than 96 files. The PC was typically infected by booting from an infected diskette. Computers, at the time, would default to booting from

390-574: Is termed dominant and the second is called recessive . This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new ( de novo ) or inherited . The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes ( autosomes ) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant , X-linked recessive or Y-linked ; these have an inheritance and presentation pattern that depends on

429-570: Is very easily modified (patched); in particular a person with no knowledge of programming can alter the message displayed. Many variants of Stoned circulated, some only with different messages. The virus has the string "Bloody! Jun. 4, 1989". On this date, the Tiananmen Square protests were suppressed by the People's Republic of China . The virus has the string "The Swedish Disaster". Manitoba has no activation routine and does not store

SECTION 10

#1732787190767

468-417: The rr (homozygous) individuals have wrinkled peas. In Rr ( heterozygous ) individuals, the R allele masks the presence of the r allele, so these individuals also have round peas. Thus, allele R is dominant over allele r , and allele r is recessive to allele R . Dominance is not inherent to an allele or its traits ( phenotype ). It is a strictly relative effect between two alleles of

507-496: The A: diskette drive if it had a diskette. The virus was spread when a floppy diskette was accessed with an infected computer. That diskette was now, itself, a source for further spread of the virus. This was much like a recessive gene - difficult to eliminate - because a user could have any number of infected diskettes and yet not have their systems infected with the virus unless they inadvertently boot from an infected diskette. Cleaning

546-642: The F1 generation are self-pollinated, the phenotypic and genotypic ratio of the F2 generation will be 1:2:1 (Red:Spotted:White). These ratios are the same as those for incomplete dominance. Again, this classical terminology is inappropriate – in reality, such cases should not be said to exhibit dominance at all. Dominance can be influenced by various genetic interactions and it is essential to evaluate them when determining phenotypic outcomes. Multiple alleles , epistasis and pleiotropic genes are some factors that might influence

585-405: The blockchain as the virus, prompting it to remove the file in question, and subsequently forcing the node to reload the block chain from that point, continuing the cycle. Only the signature of the virus had been inserted into the blockchain; the virus itself was not there, and if it were, it would not be able to function. The situation was averted shortly thereafter, when Microsoft prevented

624-408: The blockchain from being recognized as Stoned. Microsoft Security Essentials did not lose the ability to detect a real instance of Stoned. Recessive gene In genetics , dominance is the phenomenon of one variant ( allele ) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome . The first variant

663-408: The computer without cleaning all diskettes left the user susceptible to a repeat infection. The method also furthered the spread of the virus in that borrowed diskettes , if placed into the system, were now able to carry the virus to a new host. On the other hand setting a clean computer to boot preferentially from the hard disk would prevent infection in the normal course of events. The virus image

702-401: The contribution of modifier genes . In 1929, American geneticist Sewall Wright responded by stating that dominance is simply a physiological consequence of metabolic pathways and the relative necessity of the gene involved. In complete dominance, the effect of one allele in a heterozygous genotype completely masks the effect of the other. The allele that masks are considered dominant to

741-541: The dominant gene. However, if the F1-generation is further crossed with the F1-generation (heterozygote crossed with heterozygote) the offspring (F2-generation) will present the phenotype associated with the dominant gene ¾ times. Although heterozygote monohybrid crossing can result in two phenotype variants, it can result in three genotype variants -  homozygote dominant, heterozygote and homozygote recessive, respectively. In dihybrid inheritance we look at

780-406: The idea of dominance in the 1860s. However, it was not widely known until the early twentieth century. Mendel observed that, for a variety of traits of garden peas having to do with the appearance of seeds, seed pods, and plants, there were two discrete phenotypes, such as round versus wrinkled seeds, yellow versus green seeds, red versus white flowers or tall versus short plants. When bred separately,

819-417: The inheritance of two pairs of genes simultaneous. Assuming here that the two pairs of genes are located at non-homologous chromosomes, such that they are not coupled genes (see genetic linkage ) but instead inherited independently. Consider now the cross between parents (P-generation) of genotypes homozygote dominant and recessive, respectively. The offspring (F1-generation) will always heterozygous and present

SECTION 20

#1732787190767

858-485: The level of dominance the alleles expresses towards each other. Pleiotropic genes are genes where one single gene affects two or more characters (phenotype). This means that a gene can have a dominant effect on one trait, but a more recessive effect on another trait. Epistasis is interactions between multiple alleles at different loci. Easily said, several genes for one phenotype. The dominance relationship between alleles involved in epistatic interactions can influence

897-450: The locus for the beta-globin component of hemoglobin , where the three molecular phenotypes of Hb /Hb , Hb /Hb , and Hb /Hb are all distinguishable by protein electrophoresis . (The medical condition produced by the heterozygous genotype is called sickle-cell trait and is a milder condition distinguishable from sickle-cell anemia , thus the alleles show incomplete dominance concerning anemia, see above). For most gene loci at

936-455: The molecular level, both alleles are expressed co-dominantly, because both are transcribed into RNA . Co-dominance, where allelic products co-exist in the phenotype, is different from incomplete dominance, where the quantitative interaction of allele products produces an intermediate phenotype. For example, in co-dominance, a red homozygous flower and a white homozygous flower will produce offspring that have red and white spots. When plants of

975-455: The original boot sector on floppies; Manitoba simply overwrites the original boot sector. 2.88MB EHD floppies are corrupted by the virus. Manitoba uses 2KB memory while resident. NoInt tries to stop programs from detecting it. This causes read errors if the computer tries to access the partition table. Systems infected with NoInt have a decrease of 2 kB in base memory. A variant of Stoned was called Flame (later unrelated sophisticated malware

1014-513: The original master boot record is moved to cylinder 0, head 0, sector 9. Angelina contains the following embedded text, not displayed by the virus: "Greetings from ANGELINA!!!/by Garfield/Zielona Gora" ( Zielona Góra is a town in Poland). On 15 May 2014, the signature of the Stoned virus was inserted into the bitcoin blockchain . This caused Microsoft Security Essentials to recognize copies of

1053-418: The other allele, and the masked allele is considered recessive . When we only look at one trait determined by one pair of genes, we call it monohybrid inheritance . If the crossing is done between parents (P-generation, F0-generation) who are homozygote dominant and homozygote recessive, the offspring (F1-generation) will always have the heterozygote genotype and always present the phenotype associated with

1092-470: The parental hybrid plants. Mendel reasoned that each parent in the first cross was a homozygote for different alleles (one parent AA and the other parent aa), that each contributed one allele to the offspring, with the result that all of these hybrids were heterozygotes (Aa), and that one of the two alleles in the hybrid cross dominated expression of the other: A masked a. The final cross between two heterozygotes (Aa X Aa) would produce AA, Aa, and aa offspring in

1131-499: The phenotype and neither allele masks another. For example, in the ABO blood group system , chemical modifications to a glycoprotein (the H antigen) on the surfaces of blood cells are controlled by three alleles, two of which are co-dominant to each other ( I , I ) and dominant over the recessive i at the ABO locus . The I and I alleles produce different modifications. The enzyme coded for by I adds an N-acetylgalactosamine to

1170-469: The phenotype associated with the dominant allele variant. However, when crossing the F1-generation there are four possible phenotypic possibilities and the phenotypical ratio for the F2-generation will always be 9:3:3:1. Incomplete dominance (also called partial dominance , semi-dominance , intermediate inheritance , or occasionally incorrectly co-dominance in reptile genetics ) occurs when

1209-404: The phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes. The phenotypic result often appears as a blended form of characteristics in the heterozygous state. For example, the snapdragon flower color is homozygous for either red or white. When the red homozygous flower is paired with the white homozygous flower, the result yields

LZR - Misplaced Pages Continue

1248-535: The phenotypic outcome. Although any individual of a diploid organism has at most two different alleles at a given locus, most genes exist in a large number of allelic versions in the population as a whole. This is called polymorphism , and is caused by mutations. Polymorphism can have an effect on the dominance relationship and phenotype, which is observed in the ABO blood group system . The gene responsible for human blood type have three alleles; A, B, and O, and their interactions result in different blood types based on

1287-542: The phrase "Legalise Marijuana " . Later variants produced a range of other messages. The original "Your PC is now stoned. Legalise Marijuana" was thought to have been written by a student in Wellington , New Zealand. This initial version appears to have been written by someone with experience only with IBM PC 360KB floppy drives, as it misbehaves on the IBM AT 1.2MB floppy, or on systems with more than 96 files in

1326-427: The plants always produced the same phenotypes, generation after generation. However, when lines with different phenotypes were crossed (interbred), one and only one of the parental phenotypes showed up in the offspring (green, round, red, or tall). However, when these hybrid plants were crossed, the offspring plants showed the two original phenotypes, in a characteristic 3:1 ratio, the more common phenotype being that of

1365-404: The root directory. On higher capacity disks, such as 1.2 MB disks, the original boot sector may overwrite a portion of the directory. The message displays if the boot time was exactly divisible by 8. On many IBM PC clones at the time, boot times could vary, so the message would display randomly (1 time in 8). On some IBM PC compatible machines or on original IBM PC computers, the boot time

1404-456: The sex of both the parent and the child (see Sex linkage ). Since there is only one copy of the Y chromosome , Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance, such as incomplete dominance , in which a gene variant has a partial effect compared to when it is present on both chromosomes, and co-dominance , in which different variants on each chromosome both show their associated traits. Dominance

1443-420: The two homozygotes, the phenotype is said to exhibit no dominance at all, i.e. dominance exists only when the heterozygote's phenotype measure lies closer to one homozygote than the other. When plants of the F 1 generation are self-pollinated, the phenotypic and genotypic ratio of the F 2 generation will be 1:2:1 (Red:Pink:White). Co-dominance occurs when the contributions of both alleles are visible in

1482-428: Was constant, so an infected computer would either never display the message or always display the message. An infected computer with a 360K disk and a 20MB or less hard disk, which never displayed the message was one of the first examples of an asymptomatic virus carrier, which would work with no impediment to its function, but which would infect any disks inserted into it. On hard disks, the original master boot record

1521-405: Was given the same name). The early Flame uses 1 kB of DOS memory. It stores the original boot sector or master boot record at cylinder 25, head 1, sector 1 regardless of the media. Flame saves the current month of the system when it is infected. When the month changes, Flame displays colored flames on the screen and overwrites the master boot record. Angelina has stealth mechanisms. On hard disks,

#766233