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

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Understanding recombination scoring in family pedigrees

I am having some problems understanding recombination, and I am not sure what element I am missing here. This figure is an example from my text book. The pedigree belongs to a family with an autosomal ...
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563 views

Restriction Mapping - Homework question

I have trouble in solving this exercise. Exercise A circular plasmid of 10,000 base pairs (bp) is digested with two restriction enzymes,A and B, to produce a 3000 bp and a 2000 bp bands when ...
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605 views

Microsatellite shifts (peak calling) GeneMapper! Thesis help!

I'm a masters student attempting to conduct a parentage analysis on a population of fish for my thesis. My advisor and post-docs haven't been very helpful, so I need some help! I have dinucleotide ...
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What generates variation in a species?

What is the biological mechanism behind the variation within sexually reproducing species? Obviously, the children are combinations, to differing degrees, of their parents. But how does the variation ...
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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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311 views

Why don't all bacteria have F-plasmids by now?

Some bacteria can undergo gene transfer by conjugation. Conjugation is a form of horizontal gene transfer, meaning from one (unrelated) bacterium to another (in contrast to vertical gene transfer, ...
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Doubt on genomic code for nucleosome positioning?

I was reading "A genomic code for nucleosome positioning" (by Eran Segal et al). And I am having 2 doubts. The figure(b) in this image from the paper shows the graph of fraction (3-bp moving ...
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133 views

Can human mRNA be translated in vitro by prokaryotes?

As the genetic code is universal, can mRNA from a human cell be correctly translated by a prokaryote in a in vitro translation system?
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71 views

How does de-myelination occur in multiple sclerosis?

From what I understand, only the oligodendrocytes are affected in multiple sclerosis, and they are attacked by T cells which cross the blood-brain barrier. This leads me to two questions: How is the ...
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475 views

How does the colinearity of the HOX genes determine the body plan of an organism?

I was recently reading about colinearity in the HOX genes that give an organism its high-level body plan (where the order of the HOX genes on the chromosome follow the head-to-tail order of body ...
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508 views

Correlation between genome size and mutation rate?

Martin Nowak in his book "Evolutionary Dynamics" talks about a given correlation between genome size and mutation rate. What correlation does exactly exist between these two concepts? Is it a ...
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293 views

Inheritance of Huntington's disease

People with Huntington's disease have HTT genes with more than 37 copies of CAG repeat. The risk of extra copies being generated is higher during sperm formation than during ovum formation. Why is it ...
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What is a focal copy number variation?

Often, genetics studies, especially genome wide ones, talk about "focal copy number variations" in genes or regions of the chromosome. I know what a copy number variation is. What does "focal" mean, ...
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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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90 views

How are behaviors genetically coded in animals?

I am curious as to how complex behavior is passed down genetically? For example, how is the building of a web genetically coded in a spider? And how is the complex behavior of constricting prey coded ...
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49 views

what is linkage disequilibrium supposed to measure?

During reading about genetics I came across with the term of linkage disequilibrium, and I do not really understand what it supposed to mean. What is linkage disequilibrium? My current understanding ...
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105 views

Are all functions of a human cell known? [closed]

Please bear with me as I'm intruding into your world from a computer science background. In programming, once you have created a program, you know all functions of that program. Thus, 100% knowledge ...
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110 views

Components of the concept of Developmental Noise?

Developmental noise is a concept that correspond to the amount of possible phenotypic variance of a given genotype in a given environment. Intrinsic noise (aka Cellular noise) is a component of ...
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346 views

How do you merge SNP data with a reference genome?

My Data I have a 23andMe file listing SNPs in the form: ...
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What's a non-allelic gene?

Non-allelic or non-alletic I stumbled across the term in my Human Genetics textbook. It didn't explain it there, and a quick google search only showed scientific papers that refer to 'recombinations ...
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59 views

Is there are practical lower limit to gene length in E. coli?

Question is rather self-explanatory. Putting aside other post-transcriptional factors like rate of degradation of transcript, what is the smallest gene ever reported to have successfully been ...
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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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37 views

Animal gene in plants

Usually only microbes, specifically bacteria are used to express genes of other species for various functions. But, it is possible to try and express an animal gene into a plant. Bacteria like ...
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111 views

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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93 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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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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525 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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197 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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194 views

What is a genetic marker?

In DNA sequencing and analysis, what is a genetic marker? I've heard that microsatellites are genetic markers? Those are repetitive strands of bases such as GCAGCAGCAGCA etc. Why are they markers and ...
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167 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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49 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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207 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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89 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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72 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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522 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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527 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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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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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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Is the theory of evolution being disproved by bats?

For some species the Darwin's theory evolution makes perfect sense. I can easily imagine how, for example, the giraffe has evolved to its current appearance: the natural selection was favoring ...
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536 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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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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What is the instructional language of DNA?

DNA carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses (Wikipedia). Is it already know how ATCG's ...
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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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Are Italians genetically separated from other Europeans?

I was reading this Wikipedia article about the genetic history of Italy, and I found it interesting. There are however a few things that puzzle me, because they seem to contradict each other. For ...
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250 views

Why is an HIV infection considered “incurable”?

My biology teacher told me that if one caught HIV, they cannot be cured because it was near to impossible to be completely virus-free. She said this was because HIV keeps on changing its glycoprotein ...
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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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687 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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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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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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Can genes that activate transcription factors also called be called transcription factors?

If the sole known function of a gene is to activate a transcription factor, would that gene also be considered a transcription factor, or is there a word for such genes that are further upstream on ...