Name: how alleles shape inherited traits
Uploaded: 2024-08-29T22:13:37.000Z
Duration: 1 min 25 s
Channel: JoVE

K12 Standards

Arizona Science Standards

High School

Life Science

HS+B.L3

HS+B.L3U1.10

Genetic Variation

השונות הגנטית נובעת מהבדלים ברצפי הדנ"א בין פרטים, החיוניים להסתגלות ולאבולוציה של מינים.
וריאציות גנטיות נובעות מכך שהשחלות מייצרות ביציות והאשכים מייצרים זרע בתהליך הנקרא מיוזה.
השחלות משחררות ביציות שעלולות להפרות עם זרע בזמן שהן עוברות דרך החצוצרות אל הרחם.
כל ביצית וזרע תורמים 23 כרומוזומים, שהם רצפי דנ"א המקודדים גנים.
אללים הם גרסאות שונות של גנים אלה המשפיעים על תכונות ספציפיות. לדוגמה, לגן הקובע את צבע העיניים יש אללים שונים, כגון אלה עבור עיניים כחולות או חומות.
התוצאה היא זיגוטה עם 46 כרומוזומים, המשלבת חומר גנטי משני ההורים.
אנשים עם שני אללים זהים לגן נקראים הומוזיגוטים, ואילו אלה עם שני אללים שונים הם הטרוזיגוטיים.
לדוגמה, אנשים עם שני אללים מוטנטים של גן גלובין מפתחים הפרעה גנטית הנקראת אנמיה חרמשית, בעוד שאנשים הטרוזיגוטיים הנושאים אלל אחד בריא ואחד מוטציה אינם מציגים תסמיני מחלה חמורים.

שונות גנטית

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שונות גנטית היא הגיוון ברצפי ה-DNA הנמצאים בקרב פרטים מאותו מין. הגיוון הזה הוא קריטי להישרדות המין, שכן הוא מסייע לאורגניזמים להסתגל לשינויים סביבתיים. השונות הגנטית מתחילה בהפריה, שבה ביצית ותא זרע מתמזגים. כל אחד מתאים אלה נושא 23 כרומוזומים, ובסך הכל 46 כרומוזומים בביצית המופרית. הכרומוזומים הם סיבי DNA ארוכים המכילים גנים, היחידות הבסיסיות של תורשה.

גנים קיימים בגרסאות שונות הנקראות אללים, אשר יכולים להשפיע על תכונות שונות, כגון צבע שיער ועיניים, או אפילו הסיכון למחלות מסוימות. השילוב הספציפי של אללים שעוברים בתורשה משני ההורים יוצר סט ייחודי של הוראות גנטיות, שמעצב את המראה הפיזי ואת מאפייני הבריאות של הצאצא, הנקראים פנוטיפ. 

הגנוטיפ הוא הרכב הגנטי הספציפי של הפרט, שנקבע על ידי האללים שהתקבלו משני ההורים. שילוב גנטי זה משפיע על האופן שבו תכונות באות לידי ביטוי. לדוגמה, צבע העיניים מושפע מהאללים לצבע העיניים שכל הורה תורם. אם שני ההורים מספקים אלל רצסיבי לעיניים כחולות, הילד שלהם צפוי להיות בעל עיניים כחולות. מצד שני, אם אלל אחד הוא עבור עיניים חומות והאחר עבור עיניים כחולות, האלל החום הדומיננטי בדרך כלל גובר, מה שיביא לעיניים חומות אצל הילד. 

המונחים הומוזיגוט והטרוזיגוט מתארים האם שני האללים עבור גן מסוים הם זהים או שונים. היותו הומוזיגוטי פירושו ששני האללים זהים, בעוד שהיותו הטרוזיגוטי פירושו שהם שונים. הבחנה זו יכולה להשפיע באופן משמעותי על בריאותו של אדם. לדוגמה, אנמיה חרמשית היא מצב שבו אנשים עם שני אללים רצסיביים עבור גן ההמוגלובין סובלים מהמחלה. עם זאת, אלו שהם הטרוזגוטיים, נושאים אלל אחד רגיל ואלל אחד חרמשי, אינם מציגים תסמינים של המחלה אך יש להם יתרון הגנתי נגד מלריה, אשר מועיל באזורים שבהם מלריה נפוצה.
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השונות הגנטית נובעת מהבדלים ברצפי הדנ"א בין פרטים, החיוניים להסתגלות ולאבולוציה של מינים.
וריאציות גנטיות ...

Education

JoVE Core

Introduction to Psychology

מבוא לפסיכולוגיה

Unit 1

יחידה 1

Biopsychology

ביופסיכולוגיה

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

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.

Genes can appear in different versions called alleles. These alleles can affect traits such as hair and eye color. They can also influence the risk of certain diseases. The combination of alleles inherited from both parents creates a unique set of genetic instructions. These instructions shape an offspring’s physical appearance and health traits, which are called the phenotype.

An individual’s genotype is the specific genetic makeup they inherit from both parents. Genotype affects how traits are expressed. For example, eye color depends on the alleles each parent contributes. If both parents pass on a recessive allele for blue eyes, the child is likely to have blue eyes. If one allele is for brown eyes and the other is for blue eyes, the dominant brown allele usually leads to brown eyes.

The terms homozygous and heterozygous describe whether the two alleles for a gene are the same or different. Homozygous means both alleles are identical. Heterozygous means the alleles are different. This difference can affect health. People with two recessive alleles for the hemoglobin gene can have sickle cell anemia. People with one normal allele and one sickle cell allele do not show symptoms, but they have a protective advantage against malaria. This advantage is helpful in areas where malaria is common.

How Alleles Shape Inherited Traits

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

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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

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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...

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How Brain Lobes Shape Perception

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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...

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Genes, Behavior, and Mental Health

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Chromosomes, DNA, and Inherited Traits

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genetic variation

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Evolutionary Psychology and Human Behavior

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neuroplasticity

How the Brain Rewires Itself

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Brain Scanning Techniques

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Endocrine Glands and Hormone Signals

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somatosensory, motor, and association cortex

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major hormones and their functions

Hormone Imbalances and Their Effects

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inheritance

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heritability

Heritability and the Environment

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natural selection and adaptation

Adaptation in Changing Environments

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How Selection Shapes Mate Choice

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key terms and concepts

Learn how alleles, genotype, and phenotype work together to shape inherited traits, from eye color to sickle cell anemia and malaria protection.

How Alleles Shape Inherited Traits | 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

Next Generation Science Standards

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS3-2

Florida Department of Education

SC.912.L.15

SC.912.L.15.15

SC.912.L.16

SC.912.L.16.17

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS3-1.

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Mutation, Gene Flow, and Genetic Drift

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

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Natural Selection and Adaptation

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Natural Selection and Mating Preferences

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The DNA Helix

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DNA Packaging

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Organization of Genes

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Karyotyping

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RNA Structure

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RNA Stability

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Types of RNA

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MicroRNAs

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Bacterial Transformation

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What is Gene Expression?

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The Central Dogma

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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 ...

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Evolutionary Relationships through Genome Comparisons

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Genome Copying Errors

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Multi-species Conserved Sequences

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Gene Duplication and Divergence

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Exon Recombination

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

HS+B.L3U1.12

How Alleles Shape Inherited Traits

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