What is Genes: Definition and 112 Discussions

In biology, a gene (from genos (Greek) meaning generation or birth or gender) is a basic unit of heredity and a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein.During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gene–environment interactions. Some genetic traits are instantly visible, such as eye color or the number of limbs, and some are not, such as blood type, the risk for specific diseases, or the thousands of basic biochemical processes that constitute life.
Genes can acquire mutations in their sequence, leading to different variants, known as alleles, in the population. These alleles encode slightly different versions of a protein, which cause different phenotypical traits. Usage of the term "having a gene" (e.g., "good genes," "hair color gene") typically refers to containing a different allele of the same, shared gene. Genes evolve due to natural selection / survival of the fittest and genetic drift of the alleles.
The concept of gene continues to be refined as new phenomena are discovered. For example, regulatory regions of a gene can be far removed from its coding regions, and coding regions can be split into several exons. Some viruses store their genome in RNA instead of DNA and some gene products are functional non-coding RNAs. Therefore, a broad, modern working definition of a gene is any discrete locus of heritable, genomic sequence which affect an organism's traits by being expressed as a functional product or by regulation of gene expression.The term gene was introduced by Danish botanist, plant physiologist and geneticist Wilhelm Johannsen in 1909. It is inspired by the ancient Greek: γόνος, gonos, that means offspring and procreation.

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  1. B

    Sirtuins genes used to increase lifespan

    I read this book called Lifespan by a Harvard researcher called David Sinclair. They have found that Sirtuin genes (SIRT1 to SIRT7) help in repairing epi-genetic damage and have been able to extend mice lifespans by 20%. They are going to move to human trials within the next few years. Is...
  2. Eagle9

    Number of genes and their repressors

    Good day guys :smile: I want to clarify one issue in molecular biology. As well-known a repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. The number of genes in human genome is about 20 000, so how...
  3. fluidistic

    What fraction of genes do we share with relatives and with other species?

    Hello, I am reading the Selfish gene by Richard Dawkins. I am confused on genes. In some part of the book he gives us clues on how to compute the percentage of genes we have in common with relatives, such as parents and brothers and sisters, in those particular cases it is stated that we share...
  4. T

    What type of genes do I have and how do I find out?

    Hi again. About over 5 years ago I was reading something on the net about a certain human gene that is unique and rare in humans called the freak gene, super human, or slow turtle gene. Is there another name for it and does this gene exist in humans? How do I find out if I have this gene or...
  5. M

    What are Immediate Early response Genes?

    So I'm studying the MAPK pathway and Erk (MAPK) activates IEGs (Immediate Early response Genes) such as Myc, Fos and Jun. What are IEGs? I was told: IEGs: - expressed at the mRNA level (what does this mean? what's a "level"? what does "expressed" mean?) - and hence don't require protein...
  6. mark!

    Why do bacteria insert their genes into a host?

    "Acute myeloid leukaemia cells were particularly rife with bacterial sequences. A third of the microbial genes came from a genus called Acinetobacter, and had been inserted into the mitochondrial genome. "Stomach cancer cells also contained lots of bacterial DNA, especially from Pseudomonas...
  7. Buzz Bloom

    How evolution builds genes from scratch

  8. Beth N

    Backcross vs Testcross difference: Research on mitochondrial genes

    My question is all in the context of this paper. I have problems understanding a definition and a method. Sina, C. et al. Mitochondrial gene polymorphism is associated with gut microbial communities in mice. Sci. Rep. 7, 1–9 (2017). This is a segment of the introduction: " Since common inbred...
  9. jaumzaum

    Can a Single Nucleotide Mutation Significantly Change a Protein's Function?

    Hi. I'm in the first year of Medicine and I'm studying Genetics and Evolution. I have this doubt in the back of my mind and I'm not being able to move forward without someone explaining me what's wrong with my thinking. So I've learned an allele is a variant form of a gene, all alleles of the...
  10. F

    Alleles & Genes: Exploring the Basics of Human Traits

    Hello, I am trying to get some clarity on the concept of allele. Please let me know if my concepts are correct: Each human cell (almost, not all cells) has molecules of DNA, an acid, inside their nuclei. The DNA is 46 structures called chromosomes. On each chromosome, DNA is arranged as two...
  11. TytoAlba95

    How Does Recombination Frequency Affect Genetic Linkage?

    Homework Statement In a linkage map, two genes A and B, are 70 cM apart. If individuals heterozygous for both the genes are test crossed number of progeny with parental phenotype will be: 1. equal to the number of progeny with recombinant phenotype 2. more than the number of progeny with...
  12. BillTre

    Alzheimer’s May Involve Modified Genes in Brain Cells

    Brain cells from Alzheimer's patients have been found to have modifications of the amyloid precursor protein gene which forms plaques in the brains of people with Alzheimer’s disease. The modifications were duplications, partial deletions, and changes in sequence. This can result in multiple...
  13. I

    Are Luxury Genes a Direct Result of Epigenetics?

    Are luxury (smart) genes a direct result of epigenetics? I don't really see these two terms used together in articles that I come across. I just wanted to confirm whether they are in fact, directly linked? Since hemoglobin gene is expressed only in red blood cells, this would make this gene a...
  14. TytoAlba95

    Biology Genetics Problem -- six independently assorting genes in a plant

    Homework Statement A researcher studied six independently assorting genes in a plant. Each gene has a dominant and a recessive allele: R black stem, r red stem; D tall plant, d dwarf plant; C full pods, c constricted pods; O round fruit, o oval fruit; H hairless leaves, h hairy leaves; W purple...
  15. P

    Study: more genes expressed from the father

    https://www.nature.com/articles/ng.3222 And article-2577496 http://blogs.discovermagazine.com/d-brief/2015/03/03/genetically-more-like-dad/#.W1JRC8mew0M For up to 60 percent of the mouse’s genes, the copy from dad was more active than the copy from mom. This imbalance resulted in mice babies...
  16. I

    How do primates diversify their genes and avoid birth defects?

    I was wondering if there are any studies that have researched how other primates diversify their genes? Do young primates get driven away from the groups they get born into after they age to maturity? Is there a difference between what happens to males vs. females? And if some of them stick...
  17. S

    How can genes for cells change?

    I was reading about astronaut Scott Kelly's genes having "permanently" changed after a year in 0-G (the key is not that his capsule was in space, but rather that he was at 0-G, but I digress ...) Is it supposed to mean that genes have changed in new cells being born, eventually taking over as...
  18. BillTre

    37 Genes Related to Synesthesia Identified

    Synesthesia is when a normal sensory input elicits sensation normally associated with a different sensory modality, for example seeing certain colors when hearing certain sounds. I became interested in this years ago when I read "The mind of a mnemonist" by AR Luria, which described a synesthete...
  19. navneet9431

    Is light eye colour dominant or recessive trait?

    Homework Statement A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not? Homework Equations Not Any The Attempt at a Solution...
  20. BillTre

    Worm Species without Males Loses 25% of Genes

    Here is an article in the NY times about a species of round worm which evolved from having males and females to having self-fertilizing hermaphrodites. This released from selective pressure many genes involved in being male and male reproduction. They acquired random mutations until the decayed...
  21. I

    Different lengths of genes expressed

    I was wondering whether it can ever happen that only a certain "length" of the same gene gets expressed in different species? Or perhaps even within the same species? (Without it being a random mutation) Basically, can a part of a gene be expressed, and still have some functionality in the...
  22. I

    Are there duplicate genes in chromosomes and what role do they play?

    Hi, I was wondering if there are more than one genes in any cell’s chromosome that are actually identical? For example, if a certain section of the chromosome that contains the gene for eye colour that produces proteins that will give the eye a specific colour, is it just one gene that keeps...
  23. I

    Do genes "fight" to get expressed?

    I am not sure if this is an epigenetic question or not, I am not too familiar with this field, so I hope it makes sense. Do genes ever “fight” to express themselves? I guess they do initially when time comes for it to be decided which one gets expressed? Is one gene "stronger"? Is there an...
  24. J

    Relation between Mendelian genes and bases?

    Hi folks, When you study Mendelian laws you learn about dominant alleles of a gene, A, or recessive alleles of a gene. My question is, What is its relation to DNA? -So in terms of bases we have A, T, C and G. And I know a gene may be in a chromosome and it may contain several million of...
  25. T

    What are housekeeping and constitutive genes?

    I have come across two set of definitions which are not contradictory but different. From wikipedia: A constitutive gene is a gene that is transcribed continually as opposed to a facultative gene, which is only transcribed when needed. A housekeeping gene is typically a constitutive gene...
  26. I

    Why are non-coding genes called "genes"

    I thought that a gene by definition is a unit of heredity, so a portion of DNA that doesn't code for anything wouldn't be a unit of heredity and therefore shouldn't really be called a gene, no? Also if current estimates for protein coding genes in human genome is about 20000, how many total...
  27. DaveC426913

    X and Y chromosomes vs. dominant/recessive genes

    Been long time since my high school biology. I know about XX/XY chromosomes, and I know about dominant and recessive genes, but I'm a bit rusty about the connection. If father has brown eyes, and son has blue eyes, it is a foregone conclusion that father has a brown-eyed X and a blue-eyed Y...
  28. I

    Are there genes that are expressed in every cell in organism

    I know that different cells in a body express different genes and thus have different functionalities. I am wondering if there are genes that are expressed in all the cells of a certain organism. (or for that matter in all the cells that have that specific gene, for example all mammals.)? For...
  29. I

    Do Genes Code for Specific Types of Cells?

    My understanding is that genes code for proteins that then do a certain function. Apart from mitosis in an organism, I heard that cells (in forms of stem cells) are also produced and released into the body. I guess these would be all the floating around the body cells? Or the nerve cells that...
  30. Motivanka

    What is the relationship between locus, alleles, and genes in chromosomes?

    So a certain place on chromosome where gene is, it's called locus. And gene contains two allels. So in my book is said that homologous chromosomes contain set of allels and this is what confuses me. So how come is that possible if a single chromosome contains genes and each gene contain two...
  31. IfItsX

    Single-base changes, or singletons?

    The May 20, 2016 issue of Science, p876-7, "Tracking how humans evolve in real time," subtitled, "Analyses of thousands of sequenced genomes show changes in as little as a generation," uses the term "singletons" in the 4th paragraph: "...single-base changes...or singletons..." My limited...
  32. Docscientist

    Manipulating the genes of a virus

    Genetic engineering can be very helpful in obtaining organisms with desired traits.If that is the case,Why can't we modify the genes of virus and make it more lovable organisms?.I mean what if they are manipulated in such a way that they don't need a host or even if they do,they should be useful...
  33. I

    Genes and protein they code size relation?

    If the gene is smaller, is the protein that it codes for smaller too? Vice versa?
  34. cliffordlim

    Mendelian's - epitasis 9:3:4 , biology

    After I have done counting the corn and the result 267 yellow , 97 white , 144 purple ratio 9:3:4 respectively . Recessive - Epitasis ? I have no idea create a inheritance cross and the biochemical influence by genes interaction from this phenomena
  35. Drakkith

    Why Do Certain Genes Vary in Number?

    So I was reading wikipedia, browsing through various genetics-related articles, when I stumbled across the article for Amylyse, an enzym that breaks down starch into sugars. Apparently humans (and a few other animals) secrete amylyse in their saliva as a result of the expression of a certain...
  36. Eagle9

    What will happen if we relocate genes?

    We have got in human genome about 21 000 genes and they are distributed among 46 chromosomes more or less equally. Now imagine that we can relocate all these genes (I mean the genes that produce mRNAs that encodes proteins) in one/two/three/several chromosomes and all the rest chromosomes...
  37. Eagle9

    Do both strands of DNA contain genes?

    We know that the gene is part of DNA molecule in organism. I would like to know - are the both strands of DNA equally loaded/”filled” with genes? Or maybe only one strand contains genes? If both strands contain genes then can one gene on one strand “overlap” the other gene on the other strand...
  38. Drakkith

    Sharing a Percentage of Genes With Another Species

    I commonly read that humans share a certain percentage of their genes with other species, with the exact amount becoming smaller for more distantly related species. What exactly does this mean? Is it talking about the actual base pairs of our DNA, or of something else? Links to further...
  39. M

    Where Can I Find Nucleotide Chains for Genes and Chromosomes?

    I can find where a gene is usually on a particular chromosome - e.g. Chromosome 1 Mxra8 - but I can not take Mxra8 and find a source for its nucleotide chain. Help here would be appreciated. Would also appreciate if there is any source for the sequence of total bases per chromosome - e.g...
  40. C

    Searching for a Clear Description of Genes, DNA, and More

    I started reading 'Genome' by Matt Ridley thinking it would answer my questions of what genes, DNA, etc are, but I found myself frustrated with its approach. He only gives a short outline of where chromosomes and genes reside (in nuclei of cells) in the preface but there's no clear explanation...
  41. R

    How to insert genes in a plant?

    How can I insert pieces of other plant genes into another different specie of plant. I want to create new plants, so I would know the process.
  42. 2

    Why are Some Genes Dominant Over Others?

    What makes a gene dominant over another? Like why is the gene for brown eye dominant over the one for blue eyes? My teacher says it is "just like that" but I'm not so sure. IS there a reason for this?
  43. T

    Is it possible to express all mathematics through atomic pieces of computation?

    I have been considering the idea for awhile that all mathematics could be broken down into atomic pieces that are indivisible, and therefore any formula could be determined through a process of elimination by trying every possible mathematical formula. Here is what I have come up with so...
  44. edward

    News Can companies patent your genes?

    There is currently a case before the Supreme Court involving a company that has a patent on a human gene that is a predictor for breast cancer in women. http://www.cnn.com/2013/04/15/health/court-genes Bold mine...
  45. T

    Maximizing Genes: The Role of Natural Selection in Replication Success

    Does natural selection tend to result in genes that maximize their longterm growth rate (growth of the number of copies of themselves), or in genes that simply maximize the expected number of copies of themselves in the next generation? Since replication is a chance process, these are not...
  46. S

    Can death be triggred by genes

    is genes responsible for natural death in animals and human beings due to aging. can aging process be reversed by controlling biological clock
  47. J

    Genes - Why are Brothers different?

    Genes - Why are Brothers different? This question might seem childish but i still don't understand it. Why are two Brothers different. Children get 23 chromosomes from their father, and 23 chromosomes from their mother. So each child has 46 chromosomes, 23 pairs, half from the mother and...
  48. R

    What impact did the brutal conditions of early settlers have on the gene pool?

    Slave and "servant" genes. I've been reading about the shocking conditions experience by forced or "tricked" early settlers into Australia and the USA. They were more or less all slaves or experienced similar conditions. Aside from the initial journey, which would have killed anyone weak...
  49. zoobyshoe

    Uncovering the Truth Behind the Human Genome Project: Myths vs. Reality

    Years ago (I'm talking 20 years or so) I saw something on TV about the human genome project. The narrator was Asian so it might have been Michio Kaku. Anyway, I recall him having said that humans have all the genetic instructions needed to make all the other animals, while none of the other...
  50. phoenix:\\

    Study Might Link Genes to Achievement in Education

    Hm..., my knowledge is limited within this area. Are these genes certainly linked to intelligence? Not too long ago I was reading some literature explaining that no single gene (at the time) was a gene that determined intelligence, so this leads me to believe this research is more simplified and...