What is Genetics: Definition and 196 Discussions

Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.Though heredity had been observed for millennia, Gregor Mendel, Moravian scientist and Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene.
Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded beyond inheritance to studying the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the cell, the organism (e.g. dominance), and within the context of a population. Genetics has given rise to a number of subfields, including molecular genetics, epigenetics and population genetics. Organisms studied within the broad field span the domains of life (archaea, bacteria, and eukarya).
Genetic processes work in combination with an organism's environment and experiences to influence development and behavior, often referred to as nature versus nurture. The intracellular or extracellular environment of a living cell or organism may switch gene transcription on or off. A classic example is two seeds of genetically identical corn, one placed in a temperate climate and one in an arid climate (lacking sufficient waterfall or rain). While the average height of the two corn stalks may be genetically determined to be equal, the one in the arid climate only grows to half the height of the one in the temperate climate due to lack of water and nutrients in its environment.

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  1. C

    Biology DNA Sequence for Anti-Sense Strand of CCUAGGCUA mRNA Molecule

    A portion of an mRNA molecule has the sequence CCUAGGCUA. What is the sequence of the anti sense strand of the corresponding DNA molecule? The anti sense strand is the coding strand. The 3' to 5' strand from which mRNA builds. Does that mean the sequence would be backwards?
  2. B0b-A

    A low number statistics probability-problem (genetics)

    A probability problem (genetics), not homework, honest. 3 of 5 siblings are affected by an unknown inherited disease*. That this outcome is higher than 1 in 4 which is typically the case in recessive traits suggests that the disease is more likely to be dominant than recessive. Given 3...
  3. O

    Biology Genetics of Bacteria mutagenic treatment question

    Q: Which of the following mutagenic treatments would be least effective in creating a mutation in non-replicating cells? Explain your choice. a. Treatment with a deaminating agent like nitrous acid b. Treatment with an alkylating agent like MMS c. Treatment by exposure to UV d...
  4. ThomasMagnus

    Biology How Can You Determine the Genotypic Ratio of Purple Flowered F2 Plants?

    Homework Statement Mendel's explanation for the monohybrid crosses predicts that the phenotypic 3:1 ratio in the F2 can be explained by an underlying genotypic ratio of 1:2:1 (eg. 1PP:2Pp:1pp). How could you test to see if the purple flowered F2 were really in the ratio of 1PP:2Pp? Homework...
  5. S

    Can Genetics Give Us an Advantage in the Field of Finance?

    Do our genes have memory? Say that my grandfather was in finance, and my father was in finance, and i too am in finance, and have a keen interest in it, will my child have an edge in the field of finance, over the competition because 3 generation of people went into the same field...and...
  6. jbrussell93

    Take genetics elective as an elective?

    I'm a biological engineering major planning on minoring in math/physics and computational neuroscience. I'm planning on taking a cell bio and neuroscience class as BIO SCI electives, but I'm wondering if genetics would be useful. Genetics is a prerequisite for cell bio but it isn't necessarily...
  7. F

    Approximation of Gaussian integral arising in population genetics

    The following problem arises in the context of a paper on population genetics (Kimura 1962, p. 717). I have posted it here because its solution should demand only straightforward applications of tools from analysis and algebra. However, I cannot figure it out. Homework Statement Let z = 4...
  8. A

    Is it wise to take Molecular Biology without taking Genetics?

    I'm not too sure if this is the correct subforum to post this question in. Anyways I have taken Biochemistry only. I signed up to take molecular biology and I'm wondering if that is a bad idea with no previous coursework taken in genetics (the only biology college course I have taken is...
  9. S

    Biology Genetics Assignment: Analyzing IOB Mutation Reversion Rates

    Homework Statement You decide to revert an iob- mutant to wild type (IOB+) using different mutagens and find the following reversion rates for each mutagen tested: 2-amino purine - 98% 5-bromouracil - 95% Nitrous acid - 94% Proflavin - 2% Spontaneous - 4% 1. What is the most likely...
  10. U

    Biology Genetics- how many of each genotype?

    Homework Statement A germ cell in the male part of a plant (anther) (n=2) produces 4 haploid pollen cells. Assume that the gene for flower color (F) is on chromosome 1 and the gene for leaf color (L) is on chromosome 2. If a plant contains two different alleles of the flower color gene (F...
  11. F

    Biology Biology: Genetics: Inherited disease

    QUESTION 1: Homework Statement 9. Your first cousin died of Tay-Sachs disease (autosomal recessive, incidence 0.09% (about 1 in 1100)). You are not affected, nor is anyone else in your extended family. What is the approximate chance that you are a carrier? A. 5.8% B. 12.5% C. 25% D. 50% E...
  12. F

    Biology Biology: Genetics: Hardy-weinberg + restriction enzyme

    Hi, everyone, I was hoping if you can clear up some confusion for me. I have the questions and book answer to these homework problem. The hard part for me is understanding WHY these answer turn out to be the way it is. 1: Hardy-weinberg: Homework Statement 14.4 Consider a population that...
  13. B

    Do genetics and fossil record support the idea of genetic equidistance?

    Do genetics and fossil record support the idea of genetic equidistance with respect to molecular clock, or is it mostly theoretical and inferred?
  14. I

    Biochemistry or Genetics? A math concern

    Hello, this will be my first post- so, apologies if I've accidently broken any forum rules. Anyway, my question is this: Should I major in Genetics or Biochemistry? As of now, I'm leaning toward biochem (I would love either major- biochem just covers more of my interests). However, my...
  15. M

    Biology Genetics- mono and dihybrid crosses

    There is one part that I can't figure out the answer to on my genetics homework which is finding out what genotype will give 3:1 . I've tried using so ways but I really think getting those ratios is impossible; I honestly don't see any way but I really don't want to right that down. I was at...
  16. S

    Programs Pursuing PhD in Molecular Biology & Microbial Genetics

    Iam really interested in molecular biology and microbial genetics, did masters in microbiology and want to get into doctoral program and do serious research in my interesting field. Is it not the good reason to get into phd.
  17. D

    Will Genetics Limit My Future Education?

    I was born with a myriad of mental issues ranging from psychosocial-immaturity, ADHD, sensitivity to noise and various other factors that correlate closely with Asperger's syndrome. My dad is PhD in Physics with a focus in cryogenics and my mom is a French existentialist artist (weird childhood...
  18. S

    Advice and Perspective on Molcular Biology or Genetics Ph. D.

    A stab at any of my questions would be much appreciated. I've been mulling over the idea of pursuing a Ph. D.in Molecular Biology, genetics or something akin. I've missed the application deadlines for next year. However is it still possible to take classes towards the Ph. D. over next...
  19. J

    Probability in tests in genetics

    Q. A certain gene is necessary for certain protein synthesis in human beings. A new kind of test can detect the gene in people who have the gene 99.9% of the time, and falsely detects the gene 10.3% of the time when a person does not carry the gene. 93% of the population carries the gene...
  20. E

    Biology Genetics - Color Blindness Pedigree

    Homework Statement Color-blindness in humans is a sex-linked recessive trait. A color-blind man marries a woman who has normal vision and they have four children, one girl and three boys. The man has a sister who sees normally and a brother who is also color-blind, but their father (the...
  21. H

    Genetics for skeletons or bones?

    Each bone evolves independantly of the others, right? I'm pretty sure that each bone has it's own gene. Assuming I'm correct, my primary question is, did each bone also evolve its density or is there a single gene that controls the density of all bones, collectively? I hope my question is clear.
  22. S

    Biology Genetics: DNA & mRNA sequencing

    Homework Statement A portion of DNA has the sequence 3' TTGACGC 5'. The sequence of RNA that is transcribed from this sequence is Choose one answer. a. 3' UUCAGCG 5' b. 5' AACUGCG 3' c. 5' AACTGCG 3' d. 5' GCGUCAA 3' Homework Equations 3' TTGACGC 5' 5'...
  23. S

    Biology Genetics: Mapping and Recombinant Frequency

    Homework Statement Two homozygous plants are crossed and all offspring (F1) are yellow with long stems. A cross of the offspring (F1)produces the following phenotypes in the F2 generation: 1,263 yellow, long stem 1,196 white, short stem 205 yellow, short stem 195 white, long stem...
  24. S

    Biology Genetics polygenic inheritance & probability

    1. Homework Statement Height is a characteristic resulting from polygenic inheritance. If genes at four loci code for height, what is the probability that parents with the genotypes RrSSTtUu and RrSsTtUU will have a child possessing 8 tall alleles? Choose one answer. a. 1/128 b...
  25. S

    Biology Genetics: Colorblindness and Blood Type

    1. Homework Statement A colorblind man with blood type AB marries a woman with normal vision and blood type A who is heterozygous for both traits. What are the odds of having a daughter that is colorblind and has blood type A? 2. Homework Equations Xc Y IA IB x XC Xc IA i 3...
  26. S

    Biology What Offspring Result from a Homozygous Dominant Cross with an Unknown Genotype?

    [b]1. Homework Statement Crossing an individual who is homozygous dominant for a trait with an individual whose genotype is unknown will most likely produce which set of offspring? [b]2. Homework Equations DD x ? DD x Dd DD x DD DD x dd [b]3. The Attempt at a Solution...
  27. S

    Biology Understanding Genetics: Predicting Phenotypes in a Dihybrid Cross

    [b]1. Homework Statement In an organism, two separate genes influence the length of the hair. The allele for long hair, L, dominates the allele for short hair, l. The allele for hair, H, dominates the hairless allele, h. In the cross between parents of genotype LlHh and llHh, what ratio of...
  28. F

    How to Interpret Drosophila Genetics Problem with Red and White Eye Traits?

    Hello, I want to study the inheritance of red eyes and white eyes in drosophila. I have mated red-eyed females with white eyed males. F1: All F1 females were white eyed and all F1 males were red-eyed. 19 white eyed females and 22 red eyed males. I have also crossed the females and males of...
  29. N

    Biology Is the Disease in the Pedigree Diagram Inherited in an X-Linked Dominant Manner?

    I was struggling with interpreting the following pedigree diagram: http://img245.imageshack.us/img245/715/photoon20100411at2211.jpg I can see from the diagram that only females seem to be capable of transmitting the disease - not males - this lead me to believe it is X-linked. In...
  30. S

    Biology Genetics recombination questions

    Confused on 2 questions hereIf a recombination frequency between two genes is 1.5%, what is the distance between the genes in map units on the linkage map? a. Impossible to determine, because the interference is not known. b. 1.5 c. 3 d. 0.75 Recombination frequencies a. arise from completely...
  31. N

    RH Factor Genetics: O+ve with -ve Parent Possible?

    A women who was rh (-ve) and her husband is rh(+ve) and also her three children are rh (+ve) with normal delivery.the blood group is o+ve how is this possible?? Found this question at http://doubtfire.improveyourrank.in/discussion/29/geneticsrh-factor/#Item_0
  32. S

    Any hope for this PDE? Diffusion in population genetics

    I'm working on a problem in multi-allele diffusion in population genetics and I have come to this PDE: 0 = (tp_1(1-p_1)-sp_2)\frac{\partial u}{\partial p_1}+(sp_2(1-p_2)-tp_1)\frac{\partial u}{\partial p_2} + \frac{p_1(1-p_1)}{2}\frac{\partial^2 u}{\partial p_1^2} +...
  33. Z

    How are degrees of freedom determined in a Chi-square test for genetics?

    In the Chi-square test, my textbook says that degrees of freedom are the number of independent variables minus one ,df = n - 1 does this mean that that n is equal to the number of observed values from the equation aka the number of times I've added or the number of terms? sum [(O-E)^2]/E Is...
  34. F

    Biology Genetics of Flower Color Inheritance: Exploring a Monohybrid Cross

    Homework Statement A cross between two plants that both have green flowers produces 80 offspring plants, of which 36 have green flowers, 23 have black flowers, and 21 have blue flowers. Color variation is due to inheritance at one locus. What is the genotype associated with each flower...
  35. D

    Should We Stop Eating Foods with Unique DNA Fingerprints?

    I was just reading some story about how Kathy Ireland is opposed to abortion because at the moment of conception they have a 'DNA Fingerprint'. Abortion issue aside, it got me to wonder: If I sequenced my mother and father's DNA and generated all the 2^23 permutations of chromosomes would my...
  36. Dadface

    Genetic Inheritance: Exploring the Possibility of Swapping Alleles

    The following thought experiment popped into my head when I was driving from the shop; Consider one set of alleles which is responsible for one of your inherited characteristics.Now suppose that we could swap that set ,without damage or interference,with equivelent sets from one or a multiple...
  37. M

    Biology Exploring the Genetics Behind Human Diversity

    I am in AP Biology and we have been given an assignment relating to human genetics. The statement is: "Humans are genetically different; yet genetically similar at the same time." Explain why this statement is true. I have been researching day and night for the past 2 days and although I have...
  38. I

    Biology Genetics Question - Testcrossing

    Homework Statement An individual with genotype AA Bb Cc DD Ee is testcrossed. Assuming independent assortment of all gene loci, what fraction of the progeny are expected to have genotype Aa Bb Cc Dd Ee? Homework Equations Crossing AA Bb Cc Dd Ee X aa bb cc dd ee The Attempt at a...
  39. D

    Effect of learning on genetics

    hi guys.do u think some habit learned by someone can be passsed on to his or her children?
  40. B

    Genetics vectors- endosomes/lysozymes

    okay so I was talking to my friend, and they used the wrong term for a while, or said that they used the wrong term, so now I'm not 100% sure whether it's endosomes or lysozymes, but I was wondering, what are the dangers to a person who is doing gene therapy on an animal using...
  41. L

    Biology Genetics: Bacterial Genetics and Specialized Transduction

    Homework Statement Compare and contrast the transfer of the F factor and the lambda phage during conjugation under the following conditions: a) Hfr(\lambda) x F- b) Hfr x F- (\lambda) c) Hfr(\lambda) x F-(\lambda) The Attempt at a Solution a) Hfr infects F- which is non-immune -->...
  42. C

    Biology Genetics problems- punnett squares

    I need help with these: 1. Charles was married once before, & he and his first wife had a child who suffers from cystic fibrosis. His current wife Elaine's brother died of cystic fibrosis. What is the probability that Charles & Elaine will have a baby with cystic fibrosis? Let's say A=...
  43. C

    Biology Genetics Problems- some help

    1. How could you find out whether blue eyes or brown eyes is dominant? 1. My thoughts: Would you just cross a blue-eyed individual and a brown-eyed indivdual and observe what's prevalent in their offspring? 2. Gary has 6 fingers on each hand & 6 toes on each foot. His wife Sandy and daughter...
  44. S

    Biology Population Genetics: Inbreeding

    Homework Statement Dolor and her cousin Largo have conceived a child. They are very concerned about the baby, because they have heard that children of close relatives have a higher incidence of birth defects and/or inherited recessive disorders. They know that their maternal grandmother was a...
  45. T

    Future of Genetics: What Experts Think

    Hi there, sorry this question may already have been answered, several times. I tried to use the search function but couldn't come across such a thread. Long story short, I was wondering what you think of the future in Genetics? I'd imagine each embryo will be genetically modified perhaps to...
  46. S

    Mendelian Genetics, Punnet square.

    I started Genetics a couple of weeks ago and it is like a bajillion times harder than Honors Genetics Bio. I would appreciate if someone could clarify somethings and help give me an explanation on how the addition and multiplication rule works. Furthermore, my teacher says that during the AP...
  47. C

    Biology AP Biology Genetics Punnet Square

    Homework Statement A shmoo is a hypothetical genetic organism. Suppose you learned that shmoos may have long, oval or round bodies and that matings of shmoos result in the following: long x oval produced 52 long and 48 oval long x round produced 99 oval oval x oval produced 24 long, 53...
  48. C

    Biology Finding Genotypes for Dog Genetics Problem

    The question: In dogs, dark coat colour is dominant over albino, and short hair is dominant over long hair. If these effects are caused by two independently segregating gene pairs, write the most probable genotypes for the parents of each of the following crosses: (Use the symbols D and d for...
  49. S

    Biology Genetics - independent assortment and linkage

    Homework Statement In a testcross in D. melanogaster, the female heterozygote shv+/shv ; he+/h+e is crossed to a male from the homozygous recssive stock, shv/shv ; he/he. What proportion of the hairy-bodied flies has short veins? What event during meiosis causes this? How does the...
  50. L

    Biology Hello everyone,i'm havin trouble with this genetics problem.any ideas?

    Homework Statement You know grey paws(GG or Gg) is dominant to pink paws(gg).You also know that brown eyes(an x linked trait:BB,Bb, BY) is dominant to green eyes (bb or bY). You have a male dog with grey paws and brown eyes and a female dog with pink paws and brown eyes.They mate and have 8...
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