Polygenic inheritance, also known as quantitative inheritance, refers to a single inherited phenotypic trait that is controlled by two or more different genes.. There are thousands of single-gene diseases including achondroplasia, cystic fibrosis, hemophilia, Huntington disease, muscular dystrophy, and sickle cell disease.. Single-gene diseases usually follow simple Mendelian patterns of inheritance -- autosomal dominant, an autosomal recessive, or an X-linked. - Genes' Influence on Intellectual Abilities, Is Personality Genetic? This inheritance pattern portrays discontinuous variations in characters and is also referred as the qualitative inheritance. There are 4 types of genetic diseases. Examples of genetic diseases or disorders include Huntington’s disease, PCOS, and Down and Turner syndrome. LCA is a disease that primarily affects the retina. However, if a parent inherits two mutant alleles, there are no healthy alleles, so the mutant allele can exert its effect. Like other single gene disorders, X-linked disorders can be either recessive or dominant. In this diagram, the mother of the affected grandson has inherited a mutated copy from the grandmother, and the father has inherited a mutated copy from his family. - DNA's Influence on Temperament, Genetic Influence on Psychological Disorders, Psychology 103: Human Growth and Development, Biological and Biomedical What is Genetic Inheritance? Single-Gene Disorders of Mitochondria. Single gene inheritance is also called Mendelian or monogenetic inheritance. Single gene disorders are caused by DNA changes in one particular gene, and often have predictable inheritance patterns. - Definition, Traits & Example, Mendelian & Non-Mendelian Traits in Humans: Definition & List, RNA Processing in a Eukaryotic Cell: Splicing of Introns & Exons, Karyotype: Definition, Disorders & Analysis, DNA Replication Fork: Definition & Overview, Continuity and Discontinuity in Development, Nondisjunction in Meiosis: Definition & Examples, Psychology 108: Psychology of Adulthood and Aging, Psychology 107: Life Span Developmental Psychology, Human Growth and Development: Tutoring Solution, Human Growth and Development: Homework Help Resource, Human Growth & Development Studies for Teachers: Professional Development, UExcel Psychology of Adulthood & Aging: Study Guide & Test Prep, Human Growth & Development Syllabus Resource & Lesson Plans, English 103: Analyzing and Interpreting Literature, Environmental Science 101: Environment and Humanity. Unformatted text preview: Inheritance and Mutations in a Single-Gene Disorder Activity Student Handout INTRODUCTION Some diseases are caused by the environment.For example, exposure to chemicals or extremely bright lights can cause certain forms of blindness. Epigenetic inheritance is a mechanism that affects the way a gene is expressed without changing the DNA sequence. Single gene disease: Any genetic disorder caused by a change affecting only one gene. It is caused by the changes that occur in the DNA sequencing of a single gene. Single inheritance is one derived class having a single base class. Individuals inherit one ‘factor’ from each parent for each trait. Did you know… We have over 220 college Some alleles are dominant, meaning that only a single copy of that allele is necessary to express the trait. Genetic disorders with classical Mendelian inheritance The patterns shown by single-gene disorders in pedigrees depend chiefly on two factors: • The chromosomal location of the gene locus Autosomal (located on an autosome) X-linked (located on the X chromosome) • Whether the phenotype is dominant or recessive Dominant Recessive If the trait is dominant, it will be expressed in the person but may not be passed on to their child. If a person has one dominant allele and one recessive allele for their gene-pair, they will have brown eyes because it's the dominant trait, but they could have a child who is born with blue eyes because they carry the trait for blue eyes as well. All of her characteristics are inherited from her parents in some way. Trait segregating in a single abnormal gene from the mother by abnormal numbers chromosomes. 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