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How Selective Breeding is Used in Behavioral Genetics
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One of the methods used by behavioral geneticists is selective breeding. Selective breeding often involves selecting animals that are very different on one measure of behavior. For instance, if scientists take 20 rats and test how quickly they can solve a maze, chances are that they will get some variability in the speed with which the rats can solve the maze. Scientists would take the two fastest animals and the two slowest animals and breed them together. They would continue to do this over 20 generations, until they had a group of animals that solved the maze very rapidly and a group of animals that solved the maze very slowly. They are then able to examine potential differences in their brains and behaviors that contribute to maze solvi ...
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742 |
bio_man |
A year ago |
Birthmarks and what causes them
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Birthmarks are congenital marks on the skin that appear at birth and occasionally disappears spontaneously. The term nevus refers to a benign cutaneous tumor consisting of blood capillaries. Such tumors, which rarely spread from their original site and are not dangerous, vary in color according to whether the capillaries composing them carry arterial or venous blood. The popularly termed cherry marks and port-wine stains (shown below) are nevi on a level with the surface of the skin. Certain other vascular nevi, commonly known as strawberry or raspberry marks (scientifically known as hemangiomas), are slightly elevated above the surface. These can appear anywhere on the body's surface, including the airway within the nose. The former Soviet ...
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5238 |
bio_man |
2 years ago |
Why do archaeologists and geneticists reach different conclusions?
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An archaeologists is a scientist who studies human history by discovering and examining human remains and artifacts. The most common image of an archaeologists is someone on their hand and knees digging through dirt, carefully using a brush to dust off an artifact from the distant past. A geneticist, on the other hand, is someone who specializes in the science of genetics. This field of biology deals with the pattern of inheritance, molecular structure and function of genes, and gene behavior in context of a cell or organism. Both professionals are highly skilled, and use the same basic principles of science to test hypotheses, gather data, and make conclusions. However, why do archaeologists and geneticists sometimes reach different conclu ...
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16327 |
bio_man |
3 years ago |
Stress-activated gray hair explained
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An unexpected link in mice has been found between gray hair, the transcription factor MITF, and the innate immune in a recent study published in PLOS Biology. First, a discussion on the innate immune system: The innate immune system is the immune system you're born with. This includes your skin and other barriers which prevent disease entering the body, in addition to specialized cells that activate inflammation in response to foreign invaders. Technically, every cell in your body except for red blood cells, are capable of generating an immune response, and this includes the production of a signaling protein known as interferon. Microphthalmia-associated transcription factor (MITF) is best known for its role in regulating the many functions ...
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2460 |
bio_man |
6 years ago |
Is handedness determined by genetics?
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Approximately 10% of the world population is left-handed. What causes this anomaly?While there are several theories that try to explain this trait -- such as the positioning of the baby during the final trimester, hormone exposure during pregnancy, or epigenetic factors -- the most consistent and hardwired explanation boils down to plain old genetics. In other words, the reason you're right-handed or left-handed is because it's written in your DNA. Research suggests that handedness displays a complex inheritance pattern. For example, if both parents of a child are left-handed, there is a 26% chance of that child being left-handed. A large study of twins from 25,732 families also indicated that the heritability of handedness is roughly 24%. T ...
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5547 |
bio_man |
7 years ago |
Gene-edited cows
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Nearly 80% of U.S. dairy cows have their horns removed each year to protect their handlers and fellow cattle. But the practice, which is both painful and expensive, has come under increasing scrutiny from animal rights activists. Now, science may be coming to the rescue: A group of researchers announced last week that they successfully edited the genomes of dairy cows to make them hornless. The scientists used the transcription activator-like effector nucleases DNA editing technique to introduce a natural allele linked to hornlessness into dairy cow embryos. Five healthy calves were born, all without horns (above, left), the researchers report in a letter in Nature Biotechnology. The allele - called POLLED - is much more common in beef catt ...
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4443 |
duddy |
8 years ago |
Gut bacteria affects mood and brain function in mice
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According to a study published in the medical journal eLife, researchers found that specific combinations of gut bacteria produce substances that affect myelin content and cause social avoidance behaviors in mice. Researchers transferred fecal bacteria from the gut of depressed mice to genetically distinct mice exhibiting non-depressed behavior. The study showed that the transfer of microbiota was sufficient to induce social withdrawal behaviors and change the expression of myelin genes and myelin content in the brains of the recipient mice. In an effort to define the mechanism of gut-brain communication, researchers identified bacterial communities associated with increased levels of cresol, a substance that has the ability to pass the bloo ...
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3939 |
duddy |
8 years ago |
For these trickster birds, it's April fools everyday
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The darker bird pictured above belongs to a family of trickster birds known as the cuckoo. The common cuckoo is notorious for creeping into other birds' nests and laying their eggs, leaving the hosts to raise the chick as their own. This mechanism is known as brood parasitism, and it is quite common in the animal kingdom. However, not all cuckoos are dead-beat parents, many do raise their own young. The cuckoo birds that do use this mechanism are obligate brood parasites, meaning that they only reproduce in this fashion. The best-known example is the European common cuckoo (shown above). The shells of the eggs of brood-parasites are usually thick. They have two distinct layers with an outer chalky layer that is believed to provide resistan ...
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4725 |
duddy |
8 years ago |
This plant has the largest genome of all living organisms
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When it comes to genome size, a rare Japanese flower, called Paris japonica, is the current heavyweight champ, with 50 times more DNA than humans. It is a slow growing perennial that sports a rare, showy white star-like flower above a single whorl of about eight stem leaves. The exceptionally large genome of P. japonica is due to the fact that it's an octoploid, meaning it has four sets of chromosomes - on the contrary, humans are diploid (two sets). Its 40 chromosomes consist of 150 billion base pairs of DNA per cell, therefore making its genome the largest known genome of any living organism. In fact, the DNA from a single cell could theoretically stretch out to be longer than 300 feet (91 m). ...
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6501 |
duddy |
8 years ago |
This synthetic organism survives with less than 500 genes
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This week in Science, researchers led by genome sequencing pioneer Craig Venter report engineering a bacterium to have the smallest genome - and the fewest genes - of any freely living organism. Known as Syn 3.0, the new organism has a genome whittled down to the bare essentials needed to survive and reproduce, just 473 genes. However, the function of 149 of Syn 3.0's 473 genes remain unknown. As Syn 3.0's name suggests, it’s not the first synthetic life made by Venter. In 2010, Venter's team reported that they had synthesized the sole chromosome of Mycoplasma mycoides - a bacterium with a relatively small genome - and transplanted it into a separate mycoplasma called M. capricolum, from which they had previously extracted the DNA. After s ...
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10818 |
duddy |
8 years ago |
Allergic to vibrations?
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Vibratory urticarial is a ultra rare genetic condition that cause people to break out in hives if their skin is vigorously vibrated or rubbed. In fact, even drying yourself with a towel can cause hives, make your face flush, give you headaches, or produce the sensation of a metallic taste. According to a new study published this week, researchers found a mutation in a gene called ADGRE2 that codes for a receptor protein found on the surface of mast cells - immune cells in the skin that dump out inflammatory molecules such as histamines that increase blood flow to an area and can cause hives. The researchers observed that shaking mast cells in a dish breaks apart two subunits of this receptor protein, which prompts histamine release. In p ...
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16259 |
duddy |
8 years ago |
Schizophrenia may boil down to a specific gene, scientists find
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A landmark study, based on genetic analysis of nearly 65,000 people, has revealed that a person's risk of schizophrenia is increased if they inherit specific variants in a gene related to "synaptic pruning" - the elimination of connections between neurons. The findings represent the first time that the origin of this devastating psychiatric disease has been causally linked to specific gene variants and a biological process. They also help explain decades-old observations: synaptic pruning is particularly active during adolescence, which is the typical period of onset for schizophrenia symptoms, and brains of schizophrenic patients tend to show fewer connections between neurons. The gene, called component 4 (C4), plays a well-known role in t ...
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4523 |
bio_man |
8 years ago |
Elephants possess tumour fighting genes that prevent cancer
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Having more cells usually puts one at a higher risk for cancer - but not for the elephant. Despite packing 100 times as many cells as humans, this towering animal can keep cancer at bay thanks to extra copies of a tumor-fighting gene. Researchers found that Asian elephants harbor 30 to 40 copies of the gene that encodes the protein p53, one of the most important mechanisms for preventing cancer and maintaining cell division. If cells have DNA damage that could spawn tumors, p53 prevents them from dividing until they make repairs or spurs them to commit suicide. In contrast, humans sport only two copies of the gene for p53, and so does elephants’ closest living relative, the rock hyrax. The extra copies probably accumulated millions of yea ...
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9970 |
duddy |
8 years ago |
Homosexuality is not a choice
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Scientists have discovered evidence that homosexuality is not a lifestyle choice, but rather is rooted in a person’s biology. While specific genes have not been found, a male twin study reveals that homosexuality may be caused by chemical modifications that alter gene activity. As the fetus develops, certain genes get turned on or off depending the chemicals the fetus is exposed to. These chemicals don't necessarily have to be chemicals ingested or inhaled by the mother, but could be an imbalance in a hormone, such as testosterone. As adults, genes can also activate and deactivated based on our environment. More research is needed, but scientists stress that these findings shouldn’t be used to produce tests for homosexuality or a misguid ...
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3365 |
duddy |
8 years ago |
How one perceives beauty is merely superficial
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Beauty may be in the eye of the beholder, but what’s influencing our eye? Scientists reveal that it’s not genetics but life experiences that lead us to find one face more attractive than another. This finding furthers the on-going debate of nature versus nurture. Here's how the study went down: Researchers asked 547 pairs of identical twins and 214 pairs of same-gender fraternal twins to view 200 faces and rate them on a scale of one to seven, with one being the least attractive and seven the most attractive. A group of 660 non-twins then completed the same survey. If genes were more involved in facial preference, identical twins would have had similar ratings; if the influence of a familial environment carried more weight, fraternal twins w ...
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15665 |
duddy |
9 years ago |
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