Name: genotype, phenotype, and inheritance
Uploaded: 2019-03-11T09:21:16.000Z
Duration: 1 min 11 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Life Science

LS.10

LS.10.c

Genetic Lingo

Aleller aynı genlerin farklı biçimleridir.
 Her ebeveynden bir tane gelir ve diploit organizma oluşur.
 Her gen için aynı lokusta iki alel.
Her alel çifti belirli bir genin genotipi olarak bilinir.
 Fiziksel ve gözle görünür ifade yani fenotip, örneğin göz rengi, bu kalıtsal kombinasyonla belirlenir.
 Bu durumda genlerden biri olası renkler kahverengi ve mavi için iki alel içerir.
İki alel özdeşse genotipe homozigot, eş genli denir.
 Alel çifti farklı ise geneotip heterozigottur.
 İlginçtir ki, kahverengi göz gibi aynı fenotip farklı genotiplerden elde edilebilir.
Bunun nedeni büyük harfle gösterilen baskın alel gen kahverenginin, küçük harfle gösterilen çekinik maviye üstün gelmesidir.
 Demek ki çekinik bir alelin ortaya çıkması için mutlaka iki genin de çekinik olması gerekir.

Fay, David ve Andy Spencer. Baskın Mutasyonlar. Solucan Kitabı, 2006. [<a href="https://www.ncbi.nlm.nih.gov/books/NBK19699/" target="__blank">Source</a>].

genetik dil

<h4>Genel Bakış</h4>

Bir organizma, her bir genin iki varyantını veya alellerini, her bir ebeveynden bir tane miras alırsa diploiddir. Bu iki alel, belirli bir gen için genotipi oluşturur. Genotip terimi, bir organizmanın tam gen setini ifade etmek için de kullanılır. İki özdeş aleli olan diploid bir organizma homozigot bir genotipe sahipken, iki farklı alel heterozigot bir genotipe işaret eder. Genotiplerden kaynaklanan gözlemlenebilir özellikler, çevresel faktörlerden de etkilenebilen fenotipler olarak adlandırılır. Fenotipik ifade için iki kopya gerekiyorsa, ilişkili bir fenotip ve resesif göstermek için sadece bir kopya gerekiyorsa, bir alel baskındır.

<h4>Aleller Fenotipleri Etkileyebilir</h4>

İnsanlar, diğer hayvanların çoğu ve birçok bitki de dahil olmak üzere diploid organizmalar, somatik (cinsiyetsiz) hücrelerde yinelenen bir kromozom setine sahiptir. Bu kromozom kopyaları, benzer uzunluklara, centromer pozisyonlarına ve gen konumlarına sahip homologdur. Diploid organizmalar, her bir genin iki versiyonunu miras alır, her ebeveynden bir tane. Bu iki gen varyantı veya alelleri, iki homolog kromozom üzerinde aynı göreceli lokusta veya pozisyonda bulunur. Her kromozom birçok genetik lokus içerir ve genellikle belirli bir genin birkaç olası aleli vardır.

Diploid bir organizma tarafından miras alınan iki alel, lokusta genotipini oluşturur. Genotip terimi aynı zamanda bir organizmanın toplam gen kümesini de ifade eder. Farklı genotipler farklı fenotiplere veya gözlemlenebilir özelliklere (örneğin, göz rengi) neden olabilir. Fenotipler genotiplerin bir sonucu olarak ortaya çıkar, ancak çoklu genotipler aynı fenotipe neden olabilir. Fenotipler de sıklıkla çevresel faktörlerden etkilenir.

<h4>Bir Genotip İki Özdeş veya Farklı Alelden Oluşabilir</h4>

Belirli bir gen için, kalıtsal iki alel, aynı veya farklı nükleotid sekanslarına sahip olabilir. İki özdeş alleli olan bir organizmanın homozigot bir genotipi vardır (veya bir homozigottur). İki farklı aleli olan bir organizmanın heterozigot bir genotipi vardır (yani, bir heterozigottur). İki alel farklıysa (heterozigot genotip), ancak sadece bir tanesi fenotipi etkiliyorsa, fenotipi etkileyen alel baskındır. Fenotipi etkilemeyen diğer alel resesiftir.

Başlangıçta, göz renginin tek bir gen tarafından belirlendiği düşünülüyordu ve bu nedenle genellikle genetik baskınlığı (kahverengi gözler) ve durgunluğu (mavi gözler) göstermek için kullanıldı. Bununla birlikte, bilim adamları göz rengini düzenleyen en az sekiz gen keşfettiler. Her ne kadar OCA2 geni, mavi-kahverengi göz rengi spektrumundaki varyasyonun yaklaşık dörtte üçünden sorumlu olsa da, diğer genler zaman zaman bu etkileri değiştirir veya geçersiz kılar. Bununla birlikte, göz rengi baskın ve resesif alelleri göstermek için yararlı bir örnek olabilir.

Aşağıda, genotip ve fenotip arasındaki ilişkiyi göstermek için basitleştirilmiş göz rengi örneğini kullanıyoruz. Kahverengi gözler için alel B, ve mavi gözler için alel b olarak gösterilir. Bir heterozigot, bir ebeveynden baskın bir alel ve diğerinden resesif bir alel almanın bir sonucu olarak genotip Bb olacaktır. Bu bireyin kahverengi gözleri, baskın fenotipi olurdu. Baskın alel (b) geçersiz kılar veya“gizler & rdquo; mavi gözler için resesif alel talimatlarıdır. Bu nedenle, mavi gözlü bir birey mutlaka bb genotipine sahip olurken, kahverengi gözlü bir birey BB veya Bb genotipine sahip olabilir.

<h4>Dominant ve Resesif Hastalık Kalıtım Paternleri Hastalık Riski ile İlişkilidir</h4>

Her ne kadar çoğu özellik tek bir nedensel gen yerine birden fazla gen tarafından kontrol edilse de, bu ilkeler önemli sonuçların olasılığını tahmin etmek için yararlı olabilir. Örneğin, Huntington hastalığı (HD), kontrolsüz hareketlere ve bilişsel ve duygusal rahatsızlıklara neden olan ilerleyici, nörodejeneratif bir durumdur. HD, tek bir gen bozukluğu olarak kabul edilir, çünkü diğer genler başlangıç ve ilerlemeyi değiştirmesine rağmen, tek bir gende (HTT) bir mutasyondan kaynaklanır. HD, baskın bir mutasyondan kaynaklanır, bu da tek bir mutasyona uğramış alelin hastalığın ekspresyonuna yol açtığı anlamına gelir. Ebeveynin normal ve mutasyona uğramış bir gen varyantı varsa, yavruların mutasyona uğramış alel alma ve hastalığı geliştirme şansı %50'dir. HD ayrıca genellikle yaşamın ortasından sonuna kadar kendini göstermez. Bu nedenle, gerçeklik tatsız olsa da, etkilenen bir ebeveyni olan bir kişi, nedensel alele sahip olup olmadığını belirlemek ve aile planlamasını bilgilendirmek için genetik testlerden geçebilir.

Genetik Dil

Genel bakış

Bir organizma, her bir ebeveynden bir tane olmak üzere, her genin iki varyantını veya alelini miras alırsa diploiddir. Bu iki alel genotipi oluşturur ...

Education

JoVE Core

Biology

Biyoloji

Genetics

Genetik

Classical and Modern Genetics

Klasik ve Modern Genetik

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

genotype, phenotype, and inheritance

Genotype, phenotype, and inheritance help explain how traits and disease risk are passed from parents to offspring. In diploid organisms, including humans, most other animals, and many plants, somatic cells carry a duplicate set of chromosomes. These chromosome pairs are homologous, with similar length, centromere position, and gene locations.

Diploid organisms inherit two versions of each gene, one from each parent. These versions are called alleles, and they sit at the same relative locus, or position, on homologous chromosomes. The two alleles at a locus make up an organism’s genotype for that gene. Genotype can also mean the organism’s complete set of genes.

Different genotypes can produce different phenotypes, which are the observable traits of an organism. Eye color is one example. Phenotypes can also be shaped by environmental factors, and more than one genotype can sometimes lead to the same phenotype.

For a given gene, the two alleles may be identical or different. A homozygous genotype has two identical alleles. A heterozygous genotype has two different alleles. If a heterozygote shows the effect of only one allele, that allele is dominant, and the other is recessive.

Brown and blue eye color are often used to show dominance and recessiveness. In this simplified example, B stands for the brown-eye allele and b stands for the blue-eye allele. A person with Bb has brown eyes because the dominant B allele hides the blue-eye instructions from b. A person with blue eyes must have bb, while a person with brown eyes can have BB or Bb.

These same ideas also help explain disease inheritance. Huntington disease is a progressive neurodegenerative condition that can cause uncontrolled movements and changes in thinking and mood. It is a single-gene disorder caused by a mutation in the HTT gene, although other genes can affect when it starts and how it progresses. The mutation is dominant, so one mutated allele can cause the disease. If a parent has one normal allele and one mutated allele, each child has a 50% chance of inheriting the mutation. Because Huntington disease often appears in middle to late life, genetic testing can help affected families with planning.

Genotype, Phenotype, and Inheritance

genetic lingo

Genotype, phenotype, and inheritance help explain how traits and disease risk are passed from parents to offspring. In diploid organisms, including humans, most other animals, and many plants, somatic cells carry a duplicate set of chromosomes. These chromosome pairs are homologous, with similar length, centromere position, and gene locations. Diploid organisms inherit two versions of each gene, one from each parent. These versions are called alleles, and they sit at the same relative locus,...

punnett squares

Punnett Squares for Predicting Traits

Punnett squares help predict which traits offspring may inherit from two parents. They show possible genotypes, which are pairs of alleles, and can also show the chance of a phenotype, or visible trait, when the inheritance pattern is known. These grids work best for traits controlled by a single gene locus and passed on independently during meiosis. Punnett squares were developed in the early 1900s by Reginald Punnett. His work came after Gregor Mendel’s pea plant experiments revealed the...

monohybrid crosses

Mendel’s Pea Plant Inheritance Ratios

Gregor Mendel used pea plants to study how traits are passed from parents to offspring. His breeding experiments in the 1850s and 1860s showed that inheritance follows clear patterns. He crossed true-breeding plants that differed in one trait and found that dominant traits can hide recessive traits. Mendel focused on seven pea plant traits, and each trait had two forms controlled by a single gene locus. He noticed that true-breeding plants always produced offspring with the same phenotype, or...

dihybrid crosses

Mendel's Law of Independent Assortment

Mendel’s law of independent assortment explains how two traits can be inherited separately. Gregor Mendel tested this idea with pea plants that differed in two characteristics, such as pea color and pea shape. He used true-breeding parents that were homozygous for both traits but showed different phenotypes. In one example, Mendel crossed round, yellow peas with wrinkled, green peas. The parental generation had RRYY and rryy genotypes. Their first-generation offspring were all dihybrids,...

law of segregation

Mendel’s Pea Cross Ratios

Mendel’s pea plant crosses show how traits can disappear in one generation and return in the next. When he crossed plants, one parental trait sometimes seemed to vanish in the F1 generation and reappear in the F2 generation. Mendel used this pattern to explain why some traits are dominant and others are recessive. He proposed that traits are controlled by alleles, which are different versions of a gene. An organism inherits two copies of each gene, one from each parent. In his model, a...

law of independent assortment

Mendel’s Dihybrid Cross and Trait Ratios

Mendel’s dihybrid cross shows how two traits are inherited at the same time. A dihybrid cross is a cross in which both parents are homozygous for two distinct traits, and the F1 generation is heterozygous for both traits. Mendel used pea plants with round yellow peas and wrinkled green peas as an example. One parent had genotype YYRR, and the other had genotype yyrr. In the F1 generation, every plant showed the dominant traits, so the plants were YyRr and had yellow, round peas. The F2...

probability laws

Inheritance Risk with Sum and Product Rules

Inheritance risk can be calculated with the sum rule and the product rule. The sum rule applies to mutually exclusive events, or events that cannot happen at the same time. The product rule applies to independent events, or events that do not affect one another. These rules describe theoretical probability, which is the chance of an event before it happens. Empirical probability is different because it is based on events that have already occurred. These probability rules are useful in...

test cross

Using Test Crosses to Identify Genotypes

Test crosses are used to identify the genotype of an organism with a dominant trait. A genotype is the pair of alleles inherited for a gene, and alleles are different forms of the same gene. In diploid organisms, including humans, each gene usually has two alleles, one from each parent. An allele is recessive when its effect is hidden by another allele at the same gene location. Pea plants provide a clear example with flower color. White flowers are recessive, because one copy of the purple...

polygenic traits

Polygenic Traits in Human Height

Polygenic traits are traits controlled by more than one gene. Human height is a clear example of this kind of inheritance. Because many genes work together, the final trait can vary a lot from person to person. Researchers have found hundreds of loci, or gene locations, that influence height. There are likely many more that have not yet been identified. Many of these genes affect cartilage in the growth plates of the long bones in the arms and legs, either directly or indirectly. Height is...

pedigree analysis

Reading Family Traits in Pedigrees

Pedigrees are family trees used to track how a trait passes through generations. They help scientists and students see whether a trait is dominant or recessive, whether it is autosomal or sex-linked, what genotypes family members may have, and what phenotypes may appear in future generations. For families with a history of inherited disease, this information can be important for family planning. In plants and animals, inheritance is often studied with crosses. Monohybrid crosses can show...

multiple allele traits

Blood Type and Allele Interactions

Multiple alleles can shape traits through blood type, sickle cell anemia, incomplete dominance, and codominance. Multiple allelism means a gene has three or more allelic forms. Diploid organisms, including humans, usually carry only two alleles for each gene, but many human genes exist in multiple forms in the population. Human blood type is a clear example of multiple allelism. The blood type gene has three alleles: I A , I B , and i. These alleles help determine which blood type a person has...

epistasis

Gene Masking in Rabbit Fur Color

Epistasis describes how one gene can mask or change the effect of another gene. In high school genetics, this helps explain why many traits do not follow a simple single-gene pattern. Instead, alleles at different locations can work together to shape the final phenotype. Mendel studied seven unrelated pea traits, but most traits involve multiple gene interactions. Epistasis often happens when one gene interferes with the expression of another gene. It can also occur when genes are part of the...

nature and nurture

Genes and Environment Shape Height

Genes and environment both shape human height and other traits. Genes are the inherited instructions we get from our parents. Environment includes factors such as diet, stress, and social conditions. Many phenotypes, or observable traits, reflect both influences. Some also show up later in life, including cancer and other diseases. Height is a clear example of this interaction. Scientists estimate that 70-90% of height variation comes from genetic differences among people. The remaining 10-30%...

pleiotropy

SOX10 and Multiple Traits in Pleiotropy

Pleiotropy is when one gene affects more than one trait. The SOX10 gene is a clear example because it can influence pigmentation, hearing, and intestinal movement. These traits may seem unrelated, but they can all be linked to the same gene change. In humans, a deleted region in SOX10 can cause Waardenburg Syndrome Type 4, or WS4. WS4 is an autosomal recessive disorder, which means a person usually inherits two altered copies of the gene. Common signs include a white forelock,...

sex-linked disorders

X- and Y-Linked Disorder Patterns

X- and Y-linked disorders come from mutations in genes on the sex chromosomes. These genes, like those on autosomes, are needed for normal body function. When a mutation causes a biological problem, the condition is called sex-linked. Y-linked disorders come from changes in the Y chromosome. They affect only males, because only males carry a Y chromosome. Mutations in this small chromosome can affect male sexual function and secondary sex characteristics. One example is Y-chromosome...

x-linked traits

X-Linked Inheritance in Families

X-linked inheritance explains how traits on the X chromosome are passed through families. In most mammalian species, females have two X sex chromosomes, while males have one X and one Y. A mutation on one X chromosome may be masked in females by a normal allele on the other X. In males, that same mutation is more likely to show because there is no second normal X to balance it. Traits caused by changes on the X chromosome are called X-linked traits. Color blindness is a well-studied example.

x-inactivation

Barr Bodies and X-Chromosome Balance

Barr bodies and X-chromosome balance help explain how female mammalian cells control gene activity from the X chromosome. The human X chromosome carries far more genes than the Y chromosome. Because males usually have one X chromosome and females have two, females would make twice as many of some proteins without a control system. To prevent that imbalance, female mammalian cells inactivate nearly all the genes on one X chromosome during early embryonic development. The inactive X condenses...

non-nuclear inheritance

Maternal DNA in Mitochondria and Chloroplasts

Maternal DNA in mitochondria and chloroplasts explains how some genes are inherited outside the nucleus. Most DNA is in the nucleus, but mitochondria and chloroplasts in the cell cytoplasm also carry their own DNA and can copy it independently of nuclear DNA. Mitochondria are found in both plant and animal cells. They are called the powerhouses of eukaryotic cells because they break down glucose to make energy for cellular activity. Mitochondrial DNA has about 37 genes, and many help with...

chromosomal theory of inheritance

How Genes Map to Chromosomes

Genes map to chromosomes, and this idea explains how Mendel’s inheritance patterns work. Gregor Mendel published his pea plant breeding results in 1866. He showed that physical traits follow predictable patterns. At the time, scientists did not yet know that genes existed. Mendel used the word "factors" for the hereditary units he studied. The details behind Mendel’s laws of segregation and independent assortment were still unknown for many years. In the late 1800s, better microscopes and...

key terms and concepts

Learn how genotypes, alleles, dominant and recessive traits, and Huntington disease inheritance connect genes to visible traits and disease risk.

Genotype, Phenotype, and Inheritance | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

JoVE Core serisi, biyolojinin ana konseptlerini açıklayan 300 adet kısa ve kolay anlaşılabilir olan video dersleriyle ve günümüz laboratuvarlarında yürütülen gerçek araştırmaları gösteren 150'den fazla \"bilim insanları iş başında\" videolarıyla biyolojiye hayat vermektedir.

Next Generation Science Standards

High School

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS3-1

Florida Department of Education

SC.912.L.16

SC.912.L.16.1

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS3-1.

myJoVE Corporation

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Organization of Genes

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Mutations

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

Transcription

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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

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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

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Types of RNA

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MicroRNAs

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RNA Splicing

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Epigenetic Regulation

Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like ...

RNA Interference

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Operons

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Proteins: From Genes to Degradation

The student will investigate and understand that organisms reproduce and transmit genetic information to new generations. Key ideas include DNA has a role in making proteins that determine organism traits;

LS.10.a

What is Meiosis?

Meiosis is the process by which diploid cells divide to produce haploid daughter cells. In humans, each diploid cell contains 46 chromosomes, half from ...

Meiosis I

Meiosis is a carefully orchestrated set of cell divisions, the goal of which&#x2014;in humans&#x2014;is to produce haploid sperm or eggs, each containing ...

Meiosis II

Meiosis II is the second and final stage of meiosis. It relies on the haploid cells produced during meiosis I, each of which contain only 23 ...

Crossing Over

Unlike mitosis, meiosis aims for genetic diversity in its creation of haploid gametes. Dividing germ cells first begin this process in prophase I, where ...

Nondisjunction

During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed ...

The student will investigate and understand that organisms reproduce and transmit genetic information to new generations. Key ideas include the role of meiosis is to transfer traits to the next generation; and

LS.10.b

Overview

An organism is diploid if it inherits two variants, or alleles, of each gene, one from each parent. These two alleles constitute the genotype ...

Punnett Squares

Overview

A Punnett square displays the possible genotypes offspring can inherit from two parental genotypes. If a trait&#x2019;s inheritance pattern ...

Monohybrid Crosses

Overview

In the 1850s and 1860s, Gregor Mendel investigated inheritance by performing monohybrid crosses in pea plants. He crossed two plants that were ...

Dihybrid Crosses

Overview

To determine whether traits are inherited together or separately, Gregor Mendel crossed pea plants that differed in two traits. These parental ...

Law of Segregation

When crossing pea plants, Mendel noticed that one of the parental traits would sometimes disappear in the first generation of offspring, called the F1 ...

Law of Independent Assortment

While Mendel&#x2019;s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how ...

Test Cross

Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.

An allele is ...

Pedigree Analysis

Overview

A pedigree is a diagram displaying a family&#x2019;s history of a trait. Analyzing pedigrees can reveal (1) whether a trait is dominant or ...

X-linked Traits

In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be ...

Sex-linked Disorders

Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological ...

Nature and Nurture

Many human characteristics, like height, are shaped by both nature&mdash;in other words, by our genes&mdash;and by nurture, or our environment. For ...

The student will investigate and understand that organisms reproduce and transmit genetic information to new generations. Key ideas include Punnett squares are mathematical models used to predict the probability of traits in offspring.

Genotype, Phenotype, and Inheritance

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