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

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Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
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Is an egg classified based on the species inside it, or by the species that laid it?

Basically what I'm asking is if an animal of species x were to lay an egg, and the animal inside that egg happened to be the first member of a genetically new ...
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40 views

How the chaotropic agents help in purification of DNA molecule?

Those plants which are rich in secondary metabolites and polysaccharides DNA isolation can be done using certain chaotropic agents? can any one explain how it works?
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600 views

How are 23 chromosomes in human sperm chosen?

I'm not biologist and I have just a basic knowledge. I've been thinking for a long time about the following question: How does the body choose which 23 chromosomes should be active in human sperm and ...
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Do identical twins have the same fingerprint?

When there is every thing same from their genes to their phenotype so then why they don't have same fingerprints?
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388 views

Pedigree Analysis: Problem

I'm struggling to arrive at the answer to the following question, which appeared on a pre-test of mine and which I am now using to study the material we've learned. According to this helpful video, I ...
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42 views

What is allelic effect sizes and direction?

In a paper, Berkley, C. A., and C. Lexer. 2008. Admixture as the basis for genetic mapping. Trends in Ecology & Evolution 23:686–694, the definition of Genetic ...
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37 views

What distinguishes Mendelian Inheritance from Non-Mendelian Inheritance?

I'm having some trouble determining what exactly is the difference between Mendelian inheritance and non-Mendelian inheritance. For instance, I understand that chromosomal abnormalities such as Down's ...
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Book Recommendations: GRE Subject Test In Biochemistry, Cell And Molecular Biology

There are probably a lot of really good answers that may vary significantly in terms of content. I'm looking for a set of books that I can read in preparation for the GRE Subject Test In ...
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50 views

What is the result of modifying the reagents in the Sanger method?

If one of the dideoxynucleotides is omitted while using the Sanger method how would that affect the chain termination method of DNA sequencing?
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38 views

Are the genes for transcriptional factors close to their targets in the genome?

Transcriptional factors (activators and repressors) are proteins which regulate transcription. Being proteins, they themselves are also made from expression of certain DNA sequences/genes. For ...
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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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17 views

Why only human have noticeable difference in face? [duplicate]

Our facial appearance is pretty much different from each other unless we are talking about twin. Credit goes to crossing over of chromosome. But why can't we distinguish between other animals of same ...
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52 views

Chromosomomal walking

I'm having a great deal of trouble understanding chromosomal walking, especially in regards to this article: Control of male sexual behavior and sexual orientation in Drosophila by the fruitless ...
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89 views

Have there been any “chopstick gene” mistakes in genetics? [closed]

I've heard of the "chopstick gene" fallacy - wrongly assuming an association between genetics and some characteristic, confounded by non-genetic factors. Has this fallacy happened in real life? I'm ...
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1answer
37 views

Is there is difference between “homozygosity” and “homozygosis”? [closed]

Are these just two terms for the same phenomenon, i.e., the state of being homozygous? Merriam-Webster says so, but I know dictionaries sometimes miss the nuance of scientific terms. If they are ...
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0answers
24 views

Inbred mice has no severe phenotype outcome?

Why does 20 generation of inbred mouse have no particular strange phenotypes, but on the contrary, when on purposely inbreed dogs or tigers for specific phenotype cause severe deformation of the bone ...
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121 views

What is the difference between fixation and loss of alleles in a population?

When running a simulation in PopG, with parameters: Population size: 100 AA fitness: 1.0 Aa fitness: 1.0 aa fitness: 1.0 Mutation A to a: 1.0E-6 Mutation a to A: 1.0E-6 Migration rate between ...
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1answer
46 views

Genotype of children conceived after stem cell transplant?

If you have sickle cell disease and have a succesful stem cell or bone marrow transplant, your blood type changes to AA. But what about your future children? Do your sperm or egg cells continue to ...
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67 views

When was the last common ancestor of pig and human?

Some religions regard pigs as unclean on the grounds that pig flesh is closest in composition to human flesh. I don't believe this for one instant, but it got me thinking, just how close is pig and ...
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62 views

Write the haplotypes of the family

I'm doing old exam assignments to prepare for my finals on Monday and I've stumbled on one assignment that I'm not sure how to tackle. A family with 2 children is examined for cataracts using PCR ...
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1answer
105 views

How many, and how severe, are known single gene polymorphisms for obesity?

A fairly recent meta-analysis of studies examining the association between adult obesity and polymorphisms of the FTO gene (Peng et al., 2011). The paper looked at 59 studies and concluded that, "FTO ...
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5answers
384 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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1answer
57 views

What determines whether the maternal or paternal allele is expressed?

I am taking cell biology and have this question: During the process of gene expression, it is possible to express either the maternal allele or the paternal allele. When and how is the determination ...
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Do mutant alleles result from mutation of the wild type?

The allele that encodes for the most common form of a phenotype in natural population is called a wild type allele and all the rest of the alleles encoding forms other than the wild type are called ...
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229 views

Genetic linkage greater than 50 centimorgans

Classically, the linkage between two loci can be measured in centimorgans (cM), which represents the percent chance that these two loci will recombine an odd number of times (generating a recombinant ...
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Why are published chromosome counts for polyploids often incorrect by an integer multiplication factor of the original diploid like count?

Why are published chromosome counts (done using techniques such as root smashes) for polyploidy flowering plants often incorrect by a multiplication factor of 2 or 3 from the original diploid like ...
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Can you knockout specific receptors in an adult?

Sorry I don't have a good understanding of this topic, but I'm guessing that "receptor knockout" is related to/a part of "gene knockout"? And If I understand correctly, gene knockout is currently ...
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1answer
55 views

Do any dogs have blue iris - not just sclera? [closed]

I was looking in to the question of whether any dogs in fact have "blue eyes"... A quick search gives plenty of information on and images of dogs with blue sclera and black iris. Every "blue-eyed" ...
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1answer
187 views

Operators and Enhancers/Silencers

Wikipedia has two images, of a eukaryotic gene and of a prokaryotic gene. They show the difference that the prokaryotic gene also has an operator while the eukaryotic gene does not. Both also have ...
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34 views

Diffusion approximation to genetic drift

Textbook I am reading from the classical textbook Principles of Population Genetics, Hartl and Clark (pdf here). Introduction $f(p,x,t)$ is the distribution of allele frequency $x$ at time $t$ ...
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Effect of sex-ratio on the effective population size

As stated on this wikipedia article, the effective population size $N_e$ when the sex ratio differs from $\frac{1}{2}$ is $$N_e = \frac{4N_mN_f}{N_m+N_f}$$ I understand the biased sex-ratio ...
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1answer
114 views

Why do humans have 46 chromosomes? [duplicate]

Humans have approximately 25000 genes. Why are these genes on 46 chromosomes? Why not 40 or 50?
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1answer
67 views

How could one calculate the gene flow between two populations?

Imagine there are two populations X and Y, and for each population you have the genotypes of each individual in that population (e.g. Aa, AA, aa, etc.), but for multiple loci (e.g. AABb). How could ...
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1answer
17 views

Difference Between Gene Delivery and Gene Therapy

What is the specific difference between gene delivery and gene therapy? As far as I understand, gene delivery is the first step of gene therapy, but where does gene delivery end and gene therapy ...
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82 views

Known ways to modify the genetic structure of the 13 loci used in CODIS

After reading the answer to Does our DNA change during our lives?, I was wondering if and how it would be possible to change the structure of the 13 loci that are used in the CODIS database, in such a ...
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735 views

Are fishes evolving?

As far as I know, Fishing has been one of the important occupation since early ages, and infinite number of fishes have already been captured. As the time passes, they must've developed some sort of ...
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122 views

Can an argument be made that humans are 90% bacterial?

On the blog, All about Scientist in Microword: Microbiology, I read the post We are 90% bacteria, actually, which says that humans are 90% bacterial cells. If this is the case, then why don't we ...
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81 views

How many genes does D. melanogaster have?

Obviously there is no 100% exact number, but I came across this on flybase, the gold standard for annotation. I am confused now. "Genes located to the genome", is that what I am looking for? If so, ...
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36 views

“Signal Advance”: Unsure of meaning or contextual use

I am reading through Recombinant DNA; Genes and Genomes - A Short Course - Third Edition by James D. Watson, et. al. and I came across this paragraph in the discussion about discrete factors of ...
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30 views

Is it possible to have raw ngs data to practice

I'm looking for raw human ngs data to practice in bioinformatics. Better if it is from different machines (illumina, roche, pacsbio, etc). Panels, exomes and genomes. Anyone knows something?
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83 views

Microbiome Data

How is it possible to access microbiome data like that found here? I'd like to perform analyses on similar type of data, but cannot find OTU data like that at the Human Biome Project. Thanks for any ...
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Why do we assume that the first humans were dark-skinned?

According to the article Dark skin and blue eyes: How Europeans once looked: It is widely accepted that Man's oldest common forefather was dark skinned, and that people became more pale as they ...
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1answer
80 views

Colorblindness in females and random X chromosome inactivation

From Annenberg Learner: Because the X is inactivated randomly in cells, one cell could have the maternal X inactivated, while the adjacent cell could have the paternal X inactivated. This causes ...
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1answer
105 views

What does it mean to have a Y-DNA Haplogroup “R-M512”? [closed]

I did a DNA test to learn about my origins, but the results are highly technical. I see I have a Y-DNA Haplogroup R-M512 and a mutation (zero marker in DYS448). I Googled these terms and came across ...
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1answer
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How does plant grafting work?

Plant grafting is a process whereby a piece of one plant is inserted into another and results in a change of the original plant. For example, grafting a piece of a lemon tree into a bitter orange tree ...
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66 views

HIV and open reading frames

In Wilk et al. 2001 I saw that HIV has 3 open reading frames. In the Watts et al. 2009, I noticed they mentioned HIV has 9 open reading frames. I don't understand this very well. e.g. ...
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29 views

What is the Genetic Cause of Homosexuality? [duplicate]

So, I'm just wondering about this because I read the following in my Biology textbook about fruit fly genes: "Normal male and female flies express distinct forms of the fru gene. When females are ...
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1answer
7k views

Is diabetes mellitus a sex-linked disease?

There are two types of diabetes mellitus. a. Type 1 diabetes mellitus b. Type 2 diabetes melliuts Is either of them a sex linked disease? Can either one be inherited? My book says, "this disease is ...
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When performing mutagenesis for an assay, how do you decide on the sample size of individuals to be mutated such that all genes are covered?

If I want to study, say, gustatory response of salmons to a bile acid, I need to mutagenize a sample of salmon males. However, given that there are many genes involved in this response, what is ...