Best 127 quotes in «genetics quotes» category

A remarkably consistent finding, starting with elementary school students, is that males are better at math than females. While the difference is minor when it comes to considering average scores, there is a huge difference when it comes to math stars at the upper extreme of the distribution. For example, in 1983, for every girl scoring in the highest percentile in the math SAT, there were 11 boys. Why the difference? There have always been suggestions that testosterone is central. During development, testosterone fuels the growth of a brain region involved in mathematical thinking and giving adults testosterone enhances their math skills. Oh, okay, it's biological. But consider a paper published in science in 2008. The authors examined the relationship between math scores and sexual equality in 40 countries based on economic, educational and political indices of gender equality. The worst was Turkey, United States was middling, and naturally, the Scandinavians were tops. Low and behold, the more gender equal the country, the less of a discrepancy in math scores. By the time you get to the Scandinavian countries it's statistically insignificant. And by the time you examine the most gender equal country on earth at the time, Iceland, girls are better at math than boys. Footnote, note that the other reliable sex difference in cognition, namely better reading performance by girls than by boys doesn't disappear in more gender equal societies. It gets bigger. In other words, culture matters. We carry it with us wherever we go.

As far as the language instinct is concerned, the correlation between genes and languages is a coincidence. People store genes in their gonads and pass them to their children through their genitals; they store grammars in their brains and pass them to their children through their mouths. Gonads and brains are attached to each other in bodies, so when bodies move, genes and grammars move together. That is the only reason that geneticists find any correlation between the two.

Asians are still a small minority—14.5 million (including about one million identified as part Asian) or 4.7 percent of the population—but their impact is vastly disproportionate to their numbers. Forty-four percent of Asian-American adults have a college degree or higher, as opposed to 24 percent of the general population. Asian men have median earnings 10 percent higher than non Asian men, and that of Asian women is 15 percent higher than non-Asian women. Forty-five percent of Asians are employed in professional or management jobs as opposed to 34 percent for the country as a whole, and the figure is no less than 60 percent for Asian Indians. The Information Technology Association of America estimates that in the high-tech workforce Asians are represented at three times their proportion of the population. Asians are more likely than the American average to own homes rather than be renters. These successes are especially remarkable because no fewer than 69 percent of Asians are foreign-born, and immigrant groups have traditionally taken several generations to reach their full economic potential. Asians are vastly overrepresented at the best American universities. Although less than 5 percent of the population they account for the following percentages of the students at these universities: Harvard: 17 percent, Yale: 13 percent, Princeton: 12 percent, Columbia: 14 percent, Stanford: 25 percent. In California, the state with the largest number of Asians, they made up 14 percent of the 2005 high school graduating class but 42 percent of the freshmen on the campuses of the University of California system. At Berkeley, the most selective of all the campuses, the 2005 freshman class was an astonishing 48 percent Asian. Asians are also the least likely of any racial or ethnic group to commit crimes. In every category, whether violent crime, white-collar crime, alcohol, or sex offenses, they are arrested at about one-quarter to one-third the rate of whites, who are the next most law-abiding group. It would be a mistake, however, to paint all Asians with the same brush, as different nationalities can have distinctive profiles. For example, 40 percent of the manicurists in the United States are of Vietnamese origin and half the motel rooms in the country are owned by Asian Indians. Chinese (24 percent of all Asians) and Indians (16 percent), are extremely successful, as are Japanese and Koreans. Filipinos (18 percent) are somewhat less so, while the Hmong face considerable difficulties. Hmong earn 30 percent less than the national average, and 60 percent drop out of high school. In the Seattle public schools, 80 percent of Japanese-American students passed Washington state’s standardized math test for 10th-graders—the highest pass rate for any ethnic group. The group with the lowest pass rate—14 percent—was another “Asian/Pacific Islanders” category: Samoans. On the whole, Asians have a well-deserved reputation for high achievement.

As long as museums and universities send out expeditions to bring to light new forms of living and extinct animals and new data illustrating the interrelations of organisms and their environments, as long as anatomists desire a broad comparative basis human for anatomy, as long as even a few students feel a strong curiosity to learn about the course of evolution and relationships of animals, the old problems of taxonomy, phylogeny and evolution will gradually reassert themselves even in competition with brilliant and highly fruitful laboratory studies in cytology, genetics and physiological chemistry.

At sixteen, you still think you can escape from your father. You aren't listening to his voice speaking through your mouth, you don't see how your gestures already mirror his; you don't see him in the way you hold your body, in the way you sign your name. You don't hear his whisper in your blood.

Benjamin Franklin wrote little about race, but had a sense of racial loyalty. “[T]he Number of purely white People in the World is proportionably [sic] very small,” he observed. “ . . . I could wish their Numbers were increased.” James Madison, like Jefferson, believed the only solution to the problem of racial friction was to free the slaves and send them away. He proposed that the federal government sell off public lands in order to raise the money to buy the entire slave population and transport it overseas. He favored a Constitutional amendment to establish a colonization society to be run by the President. After two terms in office, Madison served as chief executive of the American Colonization Society, to which he devoted much time and energy. At the inaugural meeting of the society in 1816, Henry Clay described its purpose: to “rid our country of a useless and pernicious, if not dangerous portion of the population.” The following prominent Americans were not merely members but served as officers of the society: Andrew Jackson, Daniel Webster, Stephen Douglas, William Seward, Francis Scott Key, Winfield Scott, and two Chief Justices of the Supreme Court, John Marshall and Roger Taney. All opposed the presence of blacks in the United States and thought expatriation was the only long-term solution. James Monroe was such an ardent champion of colonization that the capital of Liberia is named Monrovia in gratitude for his efforts. As for Roger Taney, as chief justice he wrote in the Dred Scott decision of 1857 what may be the harshest federal government pronouncement on blacks ever written: Negroes were “beings of an inferior order, and altogether unfit to associate with the White race, either in social or political relations; and so far inferior that they have no rights which a White man is bound to respect.” Abraham Lincoln considered blacks to be—in his words—“a troublesome presence” in the United States. During the Lincoln-Douglas debates he expressed himself unambiguously: “I am not nor ever have been in favor of making voters or jurors of negroes, nor of qualifying them to hold office, nor to intermarry with white people; and I will say in addition to this that there is a physical difference between the white and black races which I believe will for ever forbid the two races living together on terms of social and political equality.” His opponent, Stephen Douglas, was even more outspoken, and made his position clear in the very first debate: “For one, I am opposed to negro citizenship in any form. I believe that this government was made on the white basis. I believe it was made by white men for the benefit of white men and their posterity forever, and I am in favor of confining the citizenship to white men—men of European birth and European descent, instead of conferring it upon negroes and Indians, and other inferior races.

...because the great beauty of embryo development, the bit that human beings find so hard to grasp, is that it is a totally decentralised process...no cell need wait for instructions from authority; every cell can act on its own information and the signals it receives from its neighbours. We do not organise societies that way...Perhaps we should try.

Genes do not make an individual homosexual. They play their part, but so does the rest of the universe.

Bhramari Om Chanting or Humming Om chanting sends positive messages to the brain and the cells in our body and can actually reprogram our health and behavior.

Elms are dying all over the place, it's Dutch elm disease. [...] It came from America on a load of logs, and it's a fungal disease. That makes it sound even more as if it might be possible to do something. The elms are all one elm, they are clones, that's why they are all succumbing. No natural resistance among the population, because no variation. Twins are clones, too. If you looked at an elm tree you'd never think it was part of all the others. You'd see an elm tree. Same when people look at me now: they see a person, not half a set of twins.

Enlightenment is making every cell, gene and DNA as the radiator of peace and harmony.

Eventually, her designed genetic material will be implanted into my egg, which first would have had my genetic material removed. Then my mother could become my baby. And someday, when I get old, I can become her baby. Then she will be mine, and I will be hers.

Except for the rare cases of plastid inheritance, the inheritance of all known cofactors can be sufficiently accounted for by the presence of genes in the chromosomes. In a word the cytoplasm may be ignored genetically.

First Law In every animal which has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used; while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, until it finally disappears. Second Law All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young.

Geneticists are a group of mathematicians who have taken over the Neanderthal Paleontology Guild. They call the shots now.

Genetics determine whether we get fuck-all or fuck; whether the party doors are opened or closed in our faces.

Don't be ashamed or proud of your genetics,for you have no contribution towards it.

Genetically we're just the third species of chimp, a physically weak but social animal. It was in our interests to communicate complex ideas so we could cooperate to hunt big, dangerous prey animals. I think as soon as humans developed language with grammar that allowed for abstract thought, we were set on a whole new evolutionary path, made by and for the spread of ideas instead of genes.

Genetics, accidents of birth or events in early childhood have left criminals' brains and bodies with measurable flaws predisposing them to committing assault, murder and other antisocial acts. .... Many offenders also have impairments in their autonomic nervous system, the system responsible for the edgy, nervous feeling that can come with emotional arousal. This leads to a fearless, risk-taking personality, perhaps to compensate for chronic under-arousal. Many convicted criminals, like the Unabomber, have slow heartbeats. It also gives them lower heart rates, which explains why heart rate is such a good predictor of criminal tendencies. The Unabomber, Ted Kaczynski, for example, had a resting heart rate of just 54 beats per minute, which put him in the bottom 3 per cent of the population.

Genes do not make you, any more than brain chemistry makes you hungry, food makes you breathe, breathing makes you die.

If the history of the last century taught us the dangers of empowering governments to determine genetic “fitness” (i.e., which person fits within the triangle, and who lives outside it), then the question that confronts our current era is what happens when this power devolves to the individual. It is a question that requires us to balance the desires of the individual— to carve out a life of happiness and achievement, without undue suffering— with the desires of a society that, in the short term, may be interested only in driving down the burden of disease and the expense of disability. And operating silently in the background is a third set of actors: our genes themselves, which reproduce and create new variants oblivious of our desires and compulsions— but, either directly or indirectly, acutely or obliquely, influence our desires and compulsions. Speaking at the Sorbonne in 1975, the cultural historian Michel Foucault once proposed that “a technology of abnormal individuals appears precisely when a regular network of knowledge and power has been established.” Foucault was thinking about a “regular network” of humans. But it could just as easily be a network of genes.

Have you ever had a weird and strong feeling that programming is a godlike kind of work? Just as the Lord created our world and the entire Universe based on molecular techniques such as DNA coding, software developers create a digital world based on IT coding.

If, as the dowager had said, we are nothing but gene carriers, why do so many of us have to lead such strangely shaped lives? Wouldn’t our genetic purpose—to transmit DNA—be served just as well if we lived simple lives, not bothering our heads with a lot of extraneous thoughts, devoted entirely to preserving life and procreating? Did it benefit the genes in any way for us to lead such intricately warped, even bizarre, lives?

If there's any interaction between genes and languages, it is often languages that influence genes, since linguistic differences between populations lessen the chance of genetic exchange between them.

If we are made in his image. How will that change in this next stage in our evolution? Where we have cloning of individuals and gene manipulation to enhance ourselves. Are we changing what that image is?

If these d'Herelle bodies were really genes, fundamentally like our chromosome genes, they would give us an utterly new angle from which to attack the gene problem. They are filterable, to some extent isolable, can be handled in test-tubes, and their properties, as shown by their effects on the bacteria, can then be studied after treatment. It would be very rash to call these bodies genes, and yet at present we must confess that there is no distinction known between the genes and them. Hence we can not categorically deny that perhaps we may be able to grind genes in a mortar and cook them in a beaker after all. Must we geneticists become bacteriologists, physiological chemists and physicists, simultaneously with being zoologists and botanists? Let us hope so.

If we define "beauty" as having blue eyes (and only blue eyes), then we will, indeed, find a "gene for beauty." If we define "intelligence" as the performance on only one kind of test, then we will, indeed, find a "gene for intelligence." The genome is only a mirror for the breadth or narrowness of human imagination.

If you are living in the electrified wireless west, then you are living a very abnormal lifestyle that your genetics has no adaptation to.

I have had my mother's wing of my genetic ancestry analyzed by the National Geographic tracing service and there it all is: the arrow moving northward from the African savannah, skirting the Mediterranean by way of the Levant, and passing through Eastern and Central Europe before crossing to the British Isles. And all of this knowable by an analysis of the cells on the inside of my mouth. I almost prefer the more rambling and indirect and journalistic investigation, which seems somehow less… deterministic.

If you think being descended from apes is bad for your self esteem, then get used to the idea that you are also descended from viruses.

I have English genetics that reside in the USA and have worked close to Space.

In every cell in every body in every living thing, strings of words make sentences, meanings locked together

I know genes are a big deal, son, but they're not the be-all and end-all." Rob slowed to a halt at the lights, wishing the dickhead behind would back off. "If they were, you'd be in a seafood salad and I'd be in prison.

Illness might progressively vanish so might identity. Grief might be diminished, but so might tenderness. Traumas might be erased but so might history. Infirmities might disappear, but so might vulnerability. Chance would become mitigated, but so, inevitably, would choice.

In all racial groups, students from wealthy households tend to score better than those who are poor, but income does not explain group differences. A study by McKinsey and Company found that white fourth graders living in poverty scored higher—by the equivalent of about half-a-year’s instruction—than black fourth graders who were not poor. These differences increase in high school. On the 2009 math and verbal SAT tests, whites from families with incomes of less than $20,000 not only had an average combined score that was 117 points (out of 1600) higher than the average for all blacks, they even outscored by 12 points blacks who came from families with incomes of $160,000 to $200,000. Educators and legislators have not ignored the problem. The race gap in achievement is such a preoccupation that in 2007, 4,000 educators and experts attended an “Achievement Gap Summit” in Sacramento. They took part in no fewer than 125 panels on ways to help blacks and Hispanics do as well as whites and Asians. Overwhelming majorities in Congress passed the No Child Left Behind Act in 2002 to improve student performance and bridge achievement gaps. The government budgeted $24.4 billion for the program for fiscal year 2007, and its requirements for “Adequate Yearly Progress” have forced change on many schools. This is only the latest effort in more than 25 years of federal involvement. The result? In 2009, Chester E. Finn, Jr., a former education official in the Reagan administration, put it this way: “This is a nearly unrelenting tale of woe and disappointment. If there’s any good news here, I can’t find it.

It is true that humans have physical differences, and some of those differences are spread geographically across the plant. But clinging to old notions about race won't help us understand the nature of those differences—both the ones we can see and the ones we can't.

I think part of the reason escapism is a predominate aspect of American arts—especially cinema—is because that’s what’s in our DNA. Our ancestors came here to avoid whatever was happening where they were originally from. Escapism is literally in our genes.

In the world of wild naturalism, there is nothing greater or higher than mortal survival tactics. Everything we do, we do as mortal beings with an unknowable date of death stuck on our head, or to be specific in the genetic clock.

It is common to assume that multi-racialism is inevitable, and that racial identity will disappear as races mix. Americans prefer to think that the “tragic mulatto,” welcome in neither community, was either a myth or a reflection of outmoded racist thinking. Research suggests things may not be so simple. A 2003 study of 90,000 middle-school and high-school students found that black/white mixed-race children had more health and psychological problems than children who were either black or white. They were more likely to be depressed, sleep badly, skip school, smoke, drink, consider suicide, and have sex. White/Asian children showed similar symptoms. The principal author concluded that the cause was “the struggle with identity formation, leading to lack of self-esteem, social isolation and problems of family dynamics in biracial households.” The authors of a 2008 study reached the same conclusion: “When it comes to engaging in risky/anti-social adolescent behavior, however, mixed race adolescents are stark outliers compared to both blacks and whites. . . . Mixed race adolescents—not having a natural peer group—need to engage in more risky behaviors to be accepted.” A study of white/Asian children found that they were twice as likely as mono-racial children—34 percent vs. 17 percent—to suffer from psychological disorders such as anxiety, depression or drug abuse. Yoonsun Choi of the University of Chicago found that in Seattle middle schools, a clear racial identity seemed to protect against certain problems. Bi-racial children were the group most likely to smoke, take drugs, have been in fights, hurt someone badly, or carry a gun. Prof. Choi believes mixed-race children suffer because no racial group accepts them. “There is some indication that a strong ethnic identity helps protect kids from these [undesirable] behaviors,” she said.

It is true that humans have physical differences, and some of those differences are spread geographically across the planet. But clinging to old notions about race won't help us understand the nature of those differences—both the ones we can see and the ones we can't.

It’s truly interesting to observe how genetics works in families, and what a huge lottery it is to inherit some of our relatives’ appearance features.

It should be clear by now that whatever Americans say about diversity, it is not a strength. If it were a strength, Americans would practice it spontaneously. It would not require “diversity management” or anti-discrimination laws. Nor would it require constant reminders of how wonderful it is. It takes no exhortations for us to appreciate things that are truly desirable: indoor plumbing, vacations, modern medicine, friendship, or cheaper gasoline. [W]hen they are free to do so, most people avoid diversity. The scientific evidence suggests why: Human beings appear to have deeply-rooted tribal instincts. They seem to prefer to live in homogeneous communities rather than endure the tension and conflict that arise from differences. If the goal of building a diverse society conflicts with some aspect of our nature, it will be very difficult to achieve. As Horace wrote in the Epistles, “Though you drive Nature out with a pitchfork, she will ever find her way back.” Some intellectuals and bohemians profess to enjoy diversity, but they appear to be a minority. Why do we insist that diversity is a strength when it is not? In the 1950s and 1960s, when segregation was being dismantled, many people believed full integration would be achieved within a generation. At that time, there were few Hispanics or Asians but with a population of blacks and whites, the United States could be described as “diverse.” It seemed vastly more forward-looking to think of this as an advantage to be cultivated rather than a weakness to be endured. Our country also seemed to be embarking on a morally superior course. Human history is the history of warfare—between nations, tribes, and religions —and many Americans believed that reconciliation between blacks and whites would lead to a new era of inclusiveness for all peoples of the world. After the immigration reforms of 1965 opened the United States to large numbers of non- Europeans, our country became more diverse than anyone in the 1950s would have imagined. Diversity often led to conflict, but it would have been a repudiation of the civil rights movement to conclude that diversity was a weakness. Americans are proud of their country and do not like to think it may have made a serious mistake. As examples of ethnic and racial tension continued to accumulate, and as the civil rights vision of effortless integration faded, there were strong ideological and even patriotic reasons to downplay or deny what was happening, or at least to hope that exhortations to “celebrate diversity” would turn what was proving to be a problem into an advantage. To criticize diversity raises the intolerable possibility that the United States has been acting on mistaken assumptions for half a century. To talk glowingly about diversity therefore became a form of cheerleading for America. It even became common to say that diversity was our greatest strength—something that would have astonished any American from the colonial era through the 1950s. There is so much emotional capital invested in the civil-rights-era goals of racial equality and harmony that virtually any critique of its assumptions is intolerable. To point out the obvious— that diversity brings conflict—is to question sacred assumptions about the ultimate insignificance of race. Nations are at their most sensitive and irrational where they are weakest. It is precisely because it is so easy to point out the weaknesses of diversity that any attempt to do so must be countered, not by specifying diversity’s strengths—which no one can do—but with accusations of racism.

I was drawn to horses as if they were magnets. It was in my blood. I must have inherited from my grandfather a genetic proclivity toward the equine species. Perhaps there's a quirk in the DNA that makes horse people different from everyone else, that instantly divides humanity into those who love horses and the others, who simply don't know.

Murder and suicide aren't genetic,' Julia said, scoffing sandwiches in the Black Swan in Helmsley after their visit to Rievaulx Terraces. 'Nathan isn't predisposed to tragedy.' Jackson wasn't so sure about that but he kept that thought to himself.

Longevity-and sanity. Eccentric old ladies on Harleys I can deal with.

Man with all his noble qualities still bears in his bodily frame the indelible stamp of his lowly origin.

Many theories have been advanced to explain racial gaps in performance, of which these are the most common: black and Hispanic schools do not get enough money, their classes are too big, students are segregated from whites, minorities do not have enough teachers of their own race. Each of these explanations has been thoroughly investigated. Urban schools, where non-whites are concentrated, often get more money than suburban white schools, so blacks and Hispanics are not short-changed in budget or class size. Teacher race has no detectable effect on learning (Asians, for example, outperform whites regardless of who teaches them), nor do whites in the classroom raise or lower the scores of students of other races. Money is not the problem. From the early 1970s to the 2006-2007 school year per-pupil spending more than doubled in real terms. The Cato Institute calculates that when capital costs are included, the Los Angeles School District spends more than $25,000 per student per year, and the District of Columbia spends more than $28,000. Neither district gets good results. Demographic change can become a vicious cycle: As more minorities and immigrants enter a school system average achievement falls. More money and effort is devoted to these groups, squeezing gifted programs, music and art, and advanced placement courses. The better-performing students leave, and standards fall further.

More than any other single trait, it is the apple’s genetic variability—its ineluctable wildness—that accounts for its ability to make itself at home in places as different from one another as New England and New Zealand, Kazakhstan and California. Wherever the apple tree goes, its offspring propose so many different variations on what it means to be an apple—at least five per apple, several thousand per tree—that a couple of these novelties are almost bound to have whatever qualities it takes to prosper in the tree’s adopted home.

MRI testing again shows what may be the underlying brain mechanism. The amygdalae are two small lobes in the brain associated with fear, arousal, and emotions. When they are active, it is thought to be a sign of vigilance, meaning that the brain is wary and wants more information. A study at Massachusetts General Hospital found that when subjects looked at photographs of faces—half were white, half were black—MRI scans found high amygdala activity. This was considered to be a normal reaction to unfamiliar faces. When the subjects looked at the photographs a second time the faces were more familiar; only the other-race faces continued to provoke high amygdala activity. This was true for both blacks and whites, suggesting that encounters with people of different races keep the brain at a higher level of watchfulness. Amygdalae notice race even when a person does not. William A. Cunningham of Ohio State University showed white subjects pictures of faces for only 30 milliseconds—not long enough for the subjects to be conscious of them—but black faces triggered greater amygdala activity than white faces. When he showed faces for a half a second—long enough for people to notice race—he found that black faces prompted greater activity in the pre-frontal areas, a part of the brain associated with detecting internal conflicts and controlling conscious behavior. This suggested the subjects were trying to suppress certain feelings about blacks. Steven Neuberg of Arizona State University attributes instinctive bias to evolution during our hunter-gatherer past. “By nature, people are group-living animals—a strategy that enhances individual survival and leads to what we might call a ‘tribal psychology’, ” he says. “It was adaptive for our ancestors to be attuned to those outside the group who posed threats such as to physical security, health or economic resources.

Many kinds of animal behavior can be explained by genetic similarity theory. Animals have a preference for close kin, and study after study has shown that they have a remarkable ability to tell kin from strangers. Frogs lay eggs in bunches, but they can be separated and left to hatch individually. When tadpoles are then put into a tank, brothers and sisters somehow recognize each other and cluster together rather than mix with tadpoles from different mothers. Female Belding’s ground squirrels may mate with more than one male before they give birth, so a litter can be a mix of full siblings and half siblings. Like tadpoles, they can tell each other apart. Full siblings cooperate more with each other than with half-siblings, fight less, and are less likely to run each other out of the territory when they grow up. Even bees know who their relatives are. In one experiment, bees were bred for 14 different degrees of relatedness—sisters, cousins, second cousins, etc.—to bees in a particular hive. When the bees were then released near the hive, guard bees had to decide which ones to let in. They distinguished between degrees of kinship with almost perfect accuracy, letting in the closest relatives and chasing away more distant kin. The correlation between relatedness and likelihood of being admitted was a remarkable 0.93. Ants are famous for cooperation and willingness to sacrifice for the colony. This is due to a quirk in ant reproduction that means worker ants are 70 percent genetically identical to each other. But even among ants, there can be greater or less genetic diversity, and the most closely related groups of ants appear to cooperate best. Linepithema humile is a tiny ant that originated in Argentina but migrated to the United States. Many ants died during the trip, and the species lost much of its genetic diversity. This made the northern branch of Linepithema humile more cooperative than the one left in Argentina, where different colonies quarrel and compete with each other. This new level of cooperation has helped the invaders link nests into supercolonies and overwhelm local species of ants. American entomologists want to protect American ants by introducing genetic diversity so as to make the newcomers more quarrelsome. Even plants cooperate with close kin and compete with strangers. Normally, when two plants are put in the same pot, they grow bigger root systems, trying to crowd each other out and get the most nutrients. A wild flower called the Sea Rocket, which grows on beaches, does not do that if the two plants come from the same “mother” plant. They recognize each others’ root secretions and avoid wasteful competition.