Name: heritability and the environment
Uploaded: 2024-10-24T14:03:06.000Z
Duration: 1 min 6 s
Channel: JoVE

K12 Standards

Arizona Science Standards

High School

Life Science

HS+B.L3

HS+B.L3U1.10

Heritability

遺伝率は、身長や目の色などの形質や身体的特性に対する遺伝的影響を測定します。
遺伝率は、グループや彼らが住んでいる条件によって異なります。
例えば、人間の身長は90%が遺伝しますが、栄養素と運動がそれに大きく影響します。
この家族のすべての子供たちのように、グループの全員が同様の環境で生活している場合、身長や性格などの特性の違いは、遺伝的要因に起因する可能性が高くなります。
逆に、子供の1人がより身体的に活動的で、より健康的な食事をしている場合、兄弟の身体的特徴の違いは、遺伝的要因ではなく環境要因によるものかもしれません。
身体的特性に関する過去のデータは、環境の影響をさらに示しています。例えば、世界の男女平均身長は、栄養状態や医療の改善を反映して、過去100年間で約10cm増加しました。

遺伝率

遺伝率は、個体間の遺伝的差異が集団内の形質のばらつきにどの程度寄与しているかを測定する統計的概念です。遺伝学の基本的な概念ですが、誤解されやすい傾向があります。遺伝率はパーセンテージで表され、ある特定の形質の集団内での変動のうち、遺伝的差異に起因する割合を反映します。ただし、遺伝率は形質がどの程度「遺伝的」であるかを決定するものではなく、異なる集団や環境の文脈によって一定ではないことを理解することが重要です。

形質の遺伝率は、調査対象の集団や特定の環境条件によって大きく変動する可能性があります。この変動は、遺伝率が本質的に文脈依存的であることを強調しています。たとえば、個体が非常に類似した環境条件を経験する集団では、身長などの形質の違いは遺伝的変異に起因する可能性が高く、その結果、遺伝率の推定値が高くなります。逆に、環境条件が多様な集団では、同じ形質でも遺伝率が低くなる可能性があります。これは環境要因が観察される変動により大きな役割を果たすためです。

さらに、遺伝率が高いからといって、形質の発達が環境の影響を受けない、ということではありません。IQなど、遺伝要素がかなり大きい形質でさえ、環境条件の変化によって大きく変わる可能性があります。これは、遺伝と環境のダイナミックな相互作用を浮き彫りにしています。たとえば、充実した教育プログラムを実施すると認知能力が高まり、環境の変化が強い遺伝的基盤を持つ形質にも影響を与えらえることを示しています。

体格などの身体的な形質の歴史的変化もこの概念を示しています。過去1世紀にわたって、さまざまな集団の平均身長が上昇したのは、主に栄養と医療の改善によるものであり、これらの集団の遺伝子の変化によるものではありません。1896年から1990年代にかけて平均身長が8.89 センチメートル上昇したことからわかるように、この増加は、遺伝的決定要因が顕著な形質に環境の改善が大きな影響を与えていることを強調しています。

さらに、類似した遺伝的背景を持っているものの、サポートがほとんどない環境から非常にサポーティブな環境まで、さまざまな環境で育った個人を対象とした研究では、形質の大きなばらつきが明らかになっています。これらの研究は、遺伝が枠組みを提供する一方で、環境要因が個人の身体的および行動的特徴を大きく形作ることを強調しています。遺伝と環境の相互作用を理解することは、遺伝率とその集団全体の形質発達における役割を理解する上で非常に重要です。

遺伝率は、身長や目の色などの形質や身体的特性に対する遺伝的影響を測定します。
遺伝率は...

Education

JoVE Core

Introduction to Psychology

心理学概論

Unit 1

ユニット1

Biopsychology

生物心理学

KEY TERMS AND CONCEPTS

主要用語と概念

heritability and the environment

Heritability describes how genetic differences contribute to trait variation in a population. It is a statistical measure, so it shows how much of the spread in a trait can be linked to genes across a group. It does not tell you how “genetic” a trait is in an individual person.

Heritability is usually expressed as a percentage. That percentage can change depending on which population is studied and what environmental conditions are present. This means heritability is context-dependent, not fixed for every group or setting.

When people in a population live in very similar environments, genetic differences may explain more of the variation in a trait. In that case, the heritability estimate can be higher. Height is one example often used to show this pattern.

When a population has wider environmental differences, the same trait may show lower heritability. Environmental factors then play a larger role in the variation that is seen. A high heritability estimate still does not mean the trait is untouched by the environment.

Traits with strong heritable components can still change when the environment changes. IQ is one example, because enriched educational programs can improve cognitive ability. The transcript also notes that average height has increased over the last century mostly because of better nutrition and healthcare, not because of genetic change.

The rise in average height was about 3.5 inches from 1896 to the 1990s. Studies of people with similar genetic backgrounds also show large differences when they grow up in environments that range from minimal to highly supportive. These examples show that genes set a framework, but the environment helps shape the final trait.

Heritability and the Environment

introduction to biological bases of psychology

introduction-to-biological-bases-of-psychology

Biological Factors Shaping Behavior and Mind

Biopsychology connects biology and psychology by showing how the body influences behavior and mental processes. It focuses on the nervous system, neurotransmitters, hormones, genetics, and evolutionary ideas. Together, these areas help explain why people think, feel, and act the way they do. The nervous system is the main foundation of biopsychology. It has two parts: the central nervous system, or CNS, and the peripheral nervous system, or PNS. The CNS includes the brain and spinal cord and...

nervous system

Nervous System: CNS, PNS, and Reflexes

The nervous system helps the body sense, move, and respond. It works through a network of nerve cells that carry signals around the body. This system has two main parts: the central nervous system and the peripheral nervous system. The central nervous system, or CNS, includes the brain and spinal cord. The brain acts as the body’s control center. It processes sensory information and helps coordinate responses. The spinal cord serves as a major pathway for signals between the brain and the rest...

neurons as communicators of the brain

Neuron Parts and Signal Transmission

Neurons are the cells that carry information through the brain and nervous system. They use electrical and chemical signals to help control body functions, from heartbeat regulation to complex thinking. Their structure is built for fast, efficient communication. The cell body, or soma, is the neuron’s control center. It contains the nucleus, which holds the cell’s genetic material and helps maintain the neuron’s health and function. The cytoplasm around it contains organelles that make...

neuronal communication

How Neurons Send Signals

Neurons send signals through electrochemical communication that supports brain and nervous system function. A key part of this process is the action potential, a rapid electrical change that starts when the neuron’s internal charge rises above a threshold. That signal then travels along the axon to the axon terminal, where it is ready to pass to another neuron. The connection point between two neurons is called a synapse. Synapses can be electrical or chemical, and each type moves information...

neurotransmitters

Brain Chemicals That Shape Mood and Movement

Neurotransmitters are chemical messengers that help neurons communicate. They play a major role in nervous system function, as well as in mood, movement, sleep, and social behavior. Serotonin is made in the brain and intestines. It is linked to well-being and happiness, and it helps regulate mood, appetite, and sleep. When serotonin levels are out of balance in the brain or in peripheral sites, depression and sleep problems can occur. Dopamine is produced in several brain areas, including the...

cerebral hemispheres

How the Brain’s Two Halves Work

The brain’s two cerebral hemispheres work together to process information and control the body. The left and right hemispheres are linked by the corpus callosum, a large bundle of nerve fibers. This connection lets the two sides share sensory and motor information, with each hemisphere controlling the opposite side of the body. The hemispheres are also specialized for different tasks. This is called lateralization, which means certain functions are handled more strongly by one side than the...

lobes of the cerebrum

How Brain Lobes Shape Perception

The cerebral cortex is divided into two hemispheres, and each hemisphere has four lobes: frontal, parietal, temporal, and occipital. Together, these lobes support the brain’s main cognitive and sensory jobs. They work as a team to help you think, feel, move, and respond to the world. The frontal lobe sits behind the forehead and acts as a control center for personality, intelligence, and voluntary muscle movement. It also contains the prefrontal cortex, a region that helps with planning,...

spinal cord

Spinal Cord Nerves and Reflexes

The spinal cord is a major part of the central nervous system. It runs from the base of the brainstem to the lumbar region of the vertebral column. It helps keep the body stable and carries signals between the brain and the rest of the body. The spinal cord sits inside the bony spine for protection. It is divided into 30 segments that match the vertebrae. Each segment connects to a specific body region through paired spinal nerves. These spinal nerves are grouped by where they leave the...

lateralization

Brain Hemisphere Specialization

Brain hemisphere specialization divides mental tasks between the left and right sides of the brain. This split can improve neural efficiency and support more complex human abilities. Each hemisphere tends to handle the work it does best, which helps cognitive processing run more smoothly. The left hemisphere is especially strong in logic and language-related tasks. It supports analytical thinking, which means breaking a problem into parts and solving it step by step. This is important for...

human genetics

Genes, Behavior, and Mental Health

Human genetics explains how genes can influence behavior, emotions, and mental health. It also shows how a person’s genetic code can shape physical traits and the risk of disease. Each individual carries a unique set of genes, so the effects can be subtle or more noticeable. Genes help direct how the brain, hormones, and cells work. These body systems are all shaped by genetic instructions, and they help produce differences in thoughts and behavior. Human genetics therefore links biology with...

genetic material

Chromosomes, DNA, and Inherited Traits

Chromosomes, DNA, and inherited traits explain how genetic information is organized in the human body. Each cell contains a nucleus, and the nucleus holds 46 chromosomes arranged in 23 pairs. These chromosomes are tightly coiled structures made of DNA, which carries the instructions passed from parents to offspring. An individual inherits one set of chromosomes from the mother through the egg and one set from the father through the sperm. This combination creates a unique genetic makeup. Of...

genetic variation

How Alleles Shape Inherited Traits

Genetic variation helps explain why individuals in the same species can look and act differently. It comes from differences in DNA sequences. This diversity matters because it helps a species survive and adapt when the environment changes. Variation starts at fertilization, when an egg and sperm cell join. Each of these cells carries 23 chromosomes, so the fertilized egg can have up to 46 chromosomes. Chromosomes are long DNA strands that contain genes, which are the basic units of heredity. <br...

behavioral genetics and its designs

How Behavior Genetics Studies Inheritance

Behavior genetics studies how inherited genes influence human behavior. It looks at how genes passed from parents to offspring help shape behavioral traits and tendencies. The field also examines how inherited factors and environmental influences work together. Researchers use family studies, twin studies, and adoption studies to separate genetic and environmental effects. Family studies track traits within biological families to find possible genetic patterns. They have helped identify...

organization of the brain

Brain Regions and Their Key Functions

The brain is the main control center of the nervous system. It processes sensory input, makes decisions, and directs body actions. Its structure is divided into the hindbrain, midbrain, and forebrain, and each part supports important functions. The hindbrain sits at the base of the brain. It helps regulate automatic life processes. The medulla oblongata controls involuntary functions such as heartbeat, breathing, and blood pressure. Nearby, the pons acts as a bridge between brain regions,...

evolutionary psychology

Evolutionary Psychology and Human Behavior

Evolutionary psychology explains human behavior and mental processes through natural selection. It uses Darwin’s idea that traits can spread when they help survival and reproduction. In this view, some common behaviors may be adaptations that were useful to our ancestors. One clear example is fear of snakes. This fear is nearly universal, which suggests that early humans who avoided snakes were more likely to survive deadly encounters. Over many generations, that caution could be passed on and...

neuroplasticity

How the Brain Rewires Itself

Neuroplasticity is the brain’s ability to change its structure and function in response to learning, experience, or injury. It allows neural circuits to reorganize over time. This flexibility supports lifelong development and adaptation. One part of this change begins when dendrites and axons grow. Dendrites receive signals, and axons send them. As they grow, the brain’s circuitry becomes more complex and can support more connections. Next, synaptogenesis occurs. Synaptogenesis is the...

brain imaging

Brain Scanning Techniques

Brain scanning techniques help scientists and doctors see the structure and activity of the human brain. These methods support the diagnosis, study, and treatment of neurological and psychiatric disorders. The main techniques include computerized axial tomography, or CT, positron-emission tomography, or PET, magnetic resonance imaging, or MRI, functional magnetic resonance imaging, or fMRI, and transcranial magnetic stimulation, or TMS. CT scans use X-ray technology to build detailed...

the endocrine system

Endocrine Glands and Hormone Signals

The endocrine system is a network of glands that send hormone signals through the body. Hormones are chemical messengers that help control many body functions. They enter the bloodstream and travel to cells with the right receptors, or target sites, so the signal can be received. Because of this, hormone effects are widespread, unlike the more localized effects of neurotransmitters. This signaling helps the body keep a stable internal environment, called homeostasis. Several major glands...

somatosensory, motor, and association cortex

somatosensory-motor-and-association-cortex

Brain Cortex Areas for Sensation and Movement

The brain cortex uses separate areas for sensation, movement, and higher thinking. The somatosensory cortex is in the parietal lobes. It helps the brain interpret touch, temperature, and proprioception, which is awareness of body position. The somatosensory cortex has an organized map of the body. Neurons at the top of this region mainly process signals from the lower body. Neurons at the bottom handle input from the upper body. This layout helps the brain locate sensory input with precision.

major hormones and their functions

Hormone Imbalances and Their Effects

Hormones are chemical messengers made by endocrine glands. They help control body functions and keep internal conditions stable. When hormone levels shift too far up or down, normal body processes can be disrupted. Several major hormones have clear roles in the body. Oxytocin is made in the hypothalamus and released by the pituitary gland. It supports social bonding, childbirth, and lactation. Low oxytocin can affect social interaction and stress response, and it may contribute to depression.

inheritance

Genes, Traits, and Mendel's Rules

Genes, traits, and Mendel's rules explain how characteristics pass from parents to offspring. Gregor Mendel's pea plant experiments changed how scientists understand heredity. His work showed that traits are controlled by discrete units inside organisms called genes. Genes usually come in pairs. One gene is inherited from each parent, and together they make a person's genotype. Genotype is the genetic blueprint for potential traits. Examples include blood type, eye color, and inherited...

gene-environment interactions

How Environment Shapes Gene Expression

Environmental factors can change how genes are expressed. Gene expression is a dynamic process, and traits can differ even in people with the same DNA. Radiation, temperature, behavior, nutrition, and stress all help shape the final outcome. The reaction range helps explain this process. It means genes set a possible range for a trait, while the environment helps decide where a person falls within that range. For example, genetics may allow a height range from 5'5" to 6'1", but nutrition,...

heritability

Heritability describes how genetic differences contribute to trait variation in a population. It is a statistical measure, so it shows how much of the spread in a trait can be linked to genes across a group. It does not tell you how “genetic” a trait is in an individual person. Heritability is usually expressed as a percentage. That percentage can change depending on which population is studied and what environmental conditions are present. This means heritability is context-dependent, not...

natural selection and adaptation

Adaptation in Changing Environments

Natural selection explains how organisms become better suited to their environments over time. It favors individuals with traits that improve survival and reproduction. Adaptation is the result. It includes genetic changes that help an organism function in specific conditions, such as extreme cold or thinner air at high altitudes. Adaptation is not only physical. Psychological adaptation also helps organisms, especially humans, succeed in their surroundings. These responses come from both...

natural selection and mating preferences

How Selection Shapes Mate Choice

Natural selection and mating preferences work together to shape how organisms survive and reproduce. Natural selection favors traits that help an organism fit its environment. Mating preferences are part of sexual selection, which influences who mates with whom and how genes are passed on. Evolutionary psychologists argue that these preferences are tied to instincts that support reproduction. For females, conception, pregnancy, and nursing create a strong need to choose mates who can offer...

criticisms of the evolutionary perspective

criticisms-of-the-evolutionary-perspective

Social Learning vs. Evolutionary Psychology

Social learning theory and evolutionary psychology offer two different ways to explain sexual behavior. A study in which strangers gave students compliments and then asked for casual sex showed a clear gender gap. None of the women said yes, while 70% of the men agreed. Evolutionary psychology explains this result by arguing that natural selection may have shaped women to be more selective about sexual partners. From this view, selectivity can help improve survival and reproductive success. It...

key terms and concepts

Learn how heritability measures genetic differences in a population, why it changes with environment, and how nutrition, education, and healthcare affect traits.

Heritability and the Environment | JoVE K12

JoVE Core Introduction to Psychology offers an engaging learning experience on the fundamental principles of psychology through concise video lessons. Students will explore important topics such as cognitive processes, emotional regulation, and neural mechanisms, establishing a strong foundation in the study of the mind and human behavior. This series provides an accessible and captivating approach to grasp the essential concepts of the discipline.

introduction to psychology

Florida Department of Education

SC.912.L.14

SC.912.L.14.6

new-york-state-science-learning-standards

New York State Science Learning Standards

Natural Selection and Evolution

HS-LS4-3.

What is Population Genetics?

A population is composed of members of the same species that simultaneously live and interact in the same area. When individuals in a population breed, ...

Hardy-Weinberg Principle

Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the ...

Mutation, Gene Flow, and Genetic Drift

In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions ...

Genetic Variation

Genetic variation stems from differences in DNA sequences among individuals, which are essential for species adaptation and evolution.
Genetic variations ...

Heritability measures the genetic influence on traits or physical characteristics such as height or eye color.
Heritability can vary depending on the ...

Natural Selection and Adaptation

Natural selection drives evolution by supporting organisms that are best adapted to their environments, enhancing their survival and reproduction rates.
...

Natural Selection and Mating Preferences

The principle of natural selection suggests that organisms better adapted to their environment are more likely to survive and reproduce.
Evolutionary ...

Use mathematics and computational thinking to explain the variation that occurs through meiosis and calculate the distribution of expressed traits in a population.

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the ...

Genomic DNA in Eukaryotes

Eukaryotes have large genomes compared to prokaryotes. To fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly inside the ...

The DNA Helix

Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

Organization of Genes

Overview

The genomes of eukaryotes can be structured in several functional categories. A strand of DNA is comprised of genes and intergenic regions. ...

Karyotyping

Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by ...

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations ...

Types of RNA

Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs ...

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns&mdash;non-coding regions of a gene&mdash;or intergenic regions&mdash;stretches of DNA ...

Transcription

Overview
Transcription is the process of synthesizing RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene ...

Translation

Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following ...

Bacterial Transformation

In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two ...

What is Gene Expression?

Overview
Gene expression is the process in which DNA&nbsp;directs the synthesis of functional products, that is, proteins. Cells can regulate gene ...

The Central Dogma

Overview

The central dogma of biology states that information encoded in the DNA is transferred to messenger RNA (mRNA), which then directs the synthesis ...

Transcription Factors

Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of ...

Construct an explanation for how the structure of DNA and RNA determine the structure of proteins that perform essential life functions.

HS+B.L3U1.11

Mutations

Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations ...

genome-size-and-the-evolution-of-new-genes

Genome Size and the Evolution of New Genes

evolutionary-relationships-through-genome-comparisons

Evolutionary Relationships through Genome Comparisons

Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is ...

Genome Copying Errors

DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a ...

Multi-species Conserved Sequences

Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was ...

Gene Duplication and Divergence

The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of ...

Exon Recombination

The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new ...

Analyze and interpret data on how mutations can lead to increased genetic variation in a population.

HS+B.L3U1.12

Heritability and the Environment

Description

Transcript

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