Genetics is the branch of biology that deals with the transmission and variation of inherited characteristics.

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How to calculate the percentage of heterozygous cells based on a gene map

I've encountered the following question and am quite stumped by it. A female with genotype AABBCC has been hybridized with a male that has the genotype aabbcc. The first generation (F1) has been ...
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54 views

How do I know which alleles the parents have?

I have the following assignment where I am to look at the "tree" (not sure the english word) and assign whether or not they can be autosomal dominant or recessive as well whether they can be X-linked ...
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75 views

Examples of genes involved in plastic responses

Adaptive plasticity involves sensing the environment and responding adaptively to it. Intuitively, I would think that this process may ask for a more or less complex genetic machinery of regulation of ...
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483 views

What is the biological mechanism underlying caffeine intolerance? (CYP1A2 or other?)

As far as I can tell, caffeine metabolism occurs primarily via the CYP1A2 enzyme. I am curious as to whether mutations in the CYP1A2 gene are associated with caffeine intolerance. Some site that is ...
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168 views

Phenotypic Variation of cattle - looking for academic sources

Can someone please point me in the direction of a good academic article on the following: What are possible sources of phenotypic variation of different 400 day weights of cattle? Furthermore how ...
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115 views

Non Coding DNA and its effect on evolution

I had a discussion with a friend of mine; from his understanding, bacteria and other small organisms have higher amounts of "coding" DNA and, as such, are able to evolve much faster than organisms ...
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43 views

How can the phenotypic effects of a tumor suppressor mutation be silenced?

I've been reading a little about the "two-hit" hypothesis for tumor suppressor genes here, which mentions that some genes exhibiting haploinsufficiency are exceptions to the hypothesis. I've read ...
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99 views

Are there ways to speed up the growth of plants?

I'm interested in what humans can do to speed up the rate of growth in a plant. I'm interested in both the context of home gardening and large-scale, institution-backed projects. Obviously, optimal ...
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64 views

Is probability for double crossing over included in distance cM? [task]

We got this task: There are 3 genes (acb) on one chromosome (linked inheritance). Distance a-c = 12cM, a-b=16cM. Probability for double crossing-over (CO) is 0,6%. Find ratio of genotypes of ...
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67 views

What method would you use to genotype SNPs in low quality samples?

What method would you use to genotype SNPs in low quality samples? I ideally want to genotype hundreds of SNPs in hundreds of scat samples (very low amount of target DNA, potentially degraded and ...
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408 views

Are there eukaryotes without introns?

This question on the function of introns in eukaryotic genes made me think: I know that more basal organisms have smaller introns and fewer alternatively spliced exons compared to mammals. But are ...
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410 views

What is the inbreeding coefficient for the female offspring of a sib-mating in a haplodiploid system?

The inbreeding coefficient of a sibling mating for a diploid organism is 0.25 (each allele has a 25% of being identical by descent in the offspring). In haplodiploid organisms, males result from ...
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240 views

Genetic expression in interspecific hybrids

Referring to interspecific hybrids, I have the following two questions:- Quoting from wikipedia:- The offspring of an interspecific cross are very often sterile; thus, hybrid sterility ...
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79 views

effect of background selection on promoter regions compared to distant enhancers?

Has anyone looked at the effect of background selection on the levels of conservation of promoter regions compared to distant enhancers? Do promoter regions have a higher conservation due to ...
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412 views

Why is the strength of genetic drift inversely proportional to the population size?

I saw a concept on the Internet that says "the strength of genetic drift is inversely proportional to the population size". I don't know why they are inversely proportional? Can somebody explain? ...
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10k views

Evolutionarily speaking, why do humans have 46 chromosomes

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Monkeys, chimpanzees, and Apes have 24 pairs (twenty-four pairs), for a total of 48. What caused humans to have 46? ...
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176 views

Gametes of two different species

I always wondered why gametes from two different species dont fuse together to form an offspring. eg a donkey (sperm) and a female dog (egg) I know this is not possible but I'm just curious.
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110 views

How to create a collection of anonymous sequences for teaching and testing? [closed]

I am looking for a large collection (>1000) of sequence files (eg. FASTA) from any real organism or a tool to create such a collection. The sequence files would be used for teaching and for testing ...
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586 views

What phenotypes can arise from gender-related aneuploidy?

Humans normally have 46 chromosomes (two copies - one from each parent - of each of the 24 chromosomes: [1:22] + [XX or XY]). Aneuploidy is an abnormal number of chromosomes - Down's syndromes is an ...
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307 views

If a gene is located on the X chromosome, does that mean males are never heterozygous for these genes?

As said in the title I am a little confused on the idea of traits located on the sex chromosomes. The example we worked on in class was haemophilia, a recessive trait located on the X chromosome. Does ...
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4k views

Is it possible for a child to grow taller than their tallest parent?

I have heard that offspring can't grow taller than either of their parents but I've also heard that sometimes some gene activation can skip generations. Is it possible for a child to grow taller than ...
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360 views

Why has grey hair evolved?

A vast majority of humans get at least some grey hair as they age. As far as I know this applies to both genders and all races. Presumably this means that at least some grey haired humans have ...
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1k views

Chromosome 2 fusion?

I read this article by Jeffrey Tomkins and Jerry Bergman claiming to debunk chromosome 2 fusion. Is there anything wrong with these conclusions? " 1.The reputed fusion site is located in a ...
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275 views

explanation of meaning of high-throughput

Almost all of the papers about bioinformatics, I faced with the high-throughput word, but I could not find any explanation about it (I think it is so easy to understand and thats why anyone explains ...
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507 views

Why is mRNA needed in the Protein translation?

The original question was to predict the basic requirements for information storage. Then the discussion moved to why is it necessary to include mRNA in the protein translation process. Why can't ...
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154 views

Theoretically, what technique would one use to modify a virus so that it only affected a subset of the population?

I'm writing a novel and i would like to know some of the equipment and techniques involved with modifying a virus. Is it feasible for a virus to be engineered to only affect certain people? It ...
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247 views

Could a sperm be altered to contain a female's genetics?

while discussing with a friend a while back on the likelihood a Funtari (a woman with both fully developed and functioning sets of genitalia) existing in real life we got into a discussion of weather ...
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454 views

Hershey and Chase experiment

http://www.youtube.com/watch?v=3QJ4CjFsflA This is a link to Hershey and Chase experiment. According to this experiment, we conclude that DNA is the genetic material. But how do we conclude that DNA ...
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89 views

How do proteins and genes participate in learning?

I am a computer scientist that studies biology and bioinformatics. In the last weeks, I have been trying to study new research directions, and I would like to deepen my knowledge on the role and ...
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226 views

Are these cats calico?

Calico cats are cats that have 3 fur colors and are always female or males two X chromosomes. I've seen many cats that will have 2 fur colors (one of them is usually white) and another, third, color ...
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8k views

Why do ladybugs have a different number of points on their backs

Everytime I see a ladybug I ask myself this question. Why does every ladybug have a different amount of points on its back? Is it because of its age? Or because of its genes? Is it inheritable?
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343 views

Genetic engineering for insulin production

In order to put human DNA inside a bacteria in order to have it create Insulin, from what type of cell would you need to take the gene for insulin? I thought it should be from any somatic cell, since ...
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77 views

How are there multiple varieties of the potato?

The potato appears to propagate by growing an 'eye'/'bud' which eventually grows into a new plant. So there would probably be single representative of the potato species in the world with all others ...
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154 views

What exactly is meant by the expression “differentially expressed”?

As far as I've seen, this expression is almost always used in relation to gene expression profiling. Unfortunately, I have no background in this area. Can someone please explain this in layman terms?
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How can a chromosome translocation in somatic cells lead to disease?

Looking at this picture... ...I get the impression that the part of chromosome is attached to other chromosome, but it is not mutated. When we assume that all genes in the translocated part are ...
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127 views

A photosynthesizing mouse?

N. Shubin's Your Inner Fish makes the point several times that there is a lot of functional similarity between some seemingly remote gene cousins. If that needed reinforcing we have the spider-goat, ...
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948 views

How do I calculate the change in allele frequency in a haploid population under selection?

From this book For simplicity, let us consider a haploid organism and assume that the frequencies of alleles $A_1$ and $A_2$ are given by $x$ and $y=1-x$, respectively. We also assume that the ...
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470 views

Double mutant analysis with null mutants

My professor was talking about double mutant analysis with null mutants, and how double mutant analysis won't work with hypomorphs. I really don't understand the concept of double mutant analysis. ...
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349 views

Are identical twins exactly the same?

http://www.scientificamerican.com/article.cfm?id=identical-twins-genes-are-not-identical According to this article some identical twins show differences with respect to their copy number variants. ...
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166 views

Results of a complete DNA sequencing - are they 100% reusable?

Is that correct that a complete DNA sequencing (the whole genome) need only to be done once (per person)? After that is done, it the complete genome can be stored and once the new genes (and their ...
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12k views

Pedigree Probability of Autosomal Recessive Trait

Here is a pedigree: The trait is autosomal recessive. The question is: What is the probability that the bottom 2 people (4 and 5) have a child with the trait? I tried doing ...
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69 views

Bayes theorem for mutations

MEN 2A is a dominant inherited disease caused by a mutation in the RET proto-oncogene. The probability of being sick when you have the mutation of the RET proto-oncogene varies with age and is assumed ...
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1k views

What is biological dark matter?

I recently stumbled upon the Biological Dark Matter wiki page. Its pretty light on details, but it appears to be genetic material found in humans that doesn't fall into currently classifications. ...
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359 views

Why does the slope of parent-offspring regression equals the heritability in the narrow sense?

Background ---- Notations and assumptions ---- let $W_{ij}$ be the fitness associated to the genotype $AiAj$. $x$ is the frequency of the allele $A1$ in the population. The frequency of the allele ...
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451 views

Negative value on linear gene expression in microarrays

I am starting to use microarrays and maybe this is a dumb question: Using Illumina microarrays, linear gene expression can be negative? Or maybe some artefacts have been introduced? And, in this ...
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157 views

How do mutations come to be shared by all cells?

It's my understanding that various hazards can damage the DNA in our cells, causing mutations. But whenever I picture this, I see the damage being done to one of our tissues (for example, our lungs ...
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78 views

Drosophila reference genome

Does anyone know the details about which line they are using to sequence as the Drosophila melanogaster reference genome?
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138 views

Explanation about cytogenetic notation

What is the correct meaning of cytogenetic notation "inv(4)(p13q22)" ? Inversions at chromosome 4, at the p arm 13 is inverted AND at q arm 22 is inverted OR Inversions at chromosome 4, the ...
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76 views

DNA sequencing problem

First off, let me start by outlining the problem: Your laboratory has established a technique for examining DNA replication in a cellular extract. To the cellular protein extract, you add ...
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Fixation rate at neutral loci

It is a classical result that the expected time for a neutral mutation to occur and to get fixed is $2 N \mu \frac{1}{2N} = \mu$, where $N$ is the population size and $\mu$ is the neutral mutation ...