Inheritance (biology)

The inheritance is the designation of an inheritance process of a genetic trait that can be traced on the basis of the family tree . Hereditary diseases are of particular interest , but in principle the term can be applied to all genetically determined properties.

Mandatory information

There are three main criteria for an exact description of inheritance, which are presented in the following order:

1. Number of Loci involved

• monogenic (often also "simple") - a locus
• oligogenic - few loci
• polygenic - many loci

2. Affected chromosomes

• autosomal loci are not on the sex chromosomes
• Gonosomal loci are on a sex chromosome
  • X-linked - Loci are on the X-chromosome (the more common case)
  • Y-chromosomal - Loci are on the Y-chromosome
  • W-chromosomal - Loci are on the W-chromosome (in birds and some reptiles)
  • Z-linked - Loci are on the Z-chromosome (in birds and some reptiles)
• Mitochondrial loci are on the mitochondrial DNA

3. Relationship between genotype and phenotype

• dominant
• recessive
• codominant
• intermediate

Supplementary information

After the mandatory information has been specified, an inheritance can be further specified by adding additional information:

Random and environmental interactions

• Penetrance
  • Completely
  • incomplete (indicate percentage)
• Expressiveness
  • invariable
  • variable
• Heritability (with polygenes and occasionally also with oligogens)

Gender interactions

• Gender-linked inheritance (generally with gonosomal loci)
• Gender-limited phenotype expression (e.g. cryptorchidism )
• Inheritance in the maternal line (for loci on the mitochondrial DNA and W-chromosomal loci)
• Inheritance in the paternal line (at Y-chromosomal loci)

Locus-locus interactions

• Epistasia with other loci (e.g. overdominance , also called superdominance)
• Coupling with other loci
• Pleiotropy
• Homozygous lethal factors
• Semi-lethal factors

Epigenetic Interactions

• Maternal or paternal imprinting phenomena

Determination of inheritance

The determination and description of the inheritance is primarily done using mathematical-statistical methods (e.g. segregation analysis ). If the loci involved are known, molecular genetic methods can also be used.

See also

• genealogy

literature

• Horst Kräusslich , Gottfried Brem (Hrsg.): Animal breeding and general agricultural teaching for veterinarians . Ferdinand Enke, Stuttgart 1997, ISBN 3-432-26621-9 .
• Adrian M. Srb, Ray D. Owen, Robert E. Edgar: General Genetics . 2nd Edition. WH Freeman & Company, San Francisco 1965, LCCN  65-019558 (English).

Individual evidence

1. ↑ Spectrum Lexicon of Biology: Maternal Heredity