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Chapter 12

メンデル遺伝学

Chapter 12

Mendelian Genetics

Overview A Punnett square displays the possible genotypes offspring can inherit from two parental genotypes. If a trait’s inheritance pattern …
Overview In the 1850s and 1860s, Gregor Mendel investigated inheritance by performing monohybrid crosses in pea plants. He crossed two plants that were …
Overview To determine whether traits are inherited together or separately, Gregor Mendel crossed pea plants that differed in two traits. These parental …
Trihybrid Crosses Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A …
While Mendel’s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how …
The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an …
Overview A pedigree is a diagram displaying a family’s history of a trait. Analyzing pedigrees can reveal (1) whether a trait is dominant or …
The Concept of Multiple Allelism Multiple allelism describes genes that exist in three or more allelic forms. Although diploid organisms, like humans, …
Gregor Mendel's work (1822 – 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid …
Agouti: A Lethal Allele Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is …
When more than one gene is responsible for a given phenotype, the trait is considered polygenic. Human height is a polygenic trait. Studies have uncovered …
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as …
Among mammals, the gender of an organism is determined by the sex chromosomes. Humans have two sex chromosomes, X and Y. Every human diploid cell has 22 …
The Y chromosome is a sex chromosome found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human …
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined …
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 …
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 …
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one …
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, …
Human blood is classified into different types based on the presence of antigens on the red blood cell's surface and antibodies in the plasma. Proper …
Blood transfusion is a therapeutic measure to restore the blood volume after extensive blood loss due to an accident or a medical procedure. Blood …
Cervid phenotype can be placed into one of two categories: efficiency, which promotes survival over extravagant morphometric growth, and luxury, which …
Zebrafish mutant phenotypes are often incompletely penetrant, only manifesting in some mutants. Interesting phenotypes that inconsistently appear can be …
X chromosome inactivation (XCI) is the random silencing of one X chromosome in females to achieve gene dosage balance between the sexes. As a result, all …