Chromosome theory of inheritance

The chromosome theory of inheritance holds that genes are located on chromosomes, which transmit them during reproduction. It explains how chromosome behavior during meiosis and fertilization accounts for inheritance patterns.

Meiosis: A cell division process that produces haploid cells by separating homologous chromosomes and then sister chromatids. Homologous chromosomes separate in meiosis, providing the cellular basis for Mendel’s segregation rule.
Gregor Mendel: The nineteenth-century monk and scientist whose pea-plant experiments established foundational rules of inheritance. Mendel’s laws supplied the inheritance patterns the chromosome theory later explained.
Gene: A heritable DNA sequence that contributes to a functional product or regulates its production. The theory places genes on chromosomes as discrete hereditary units.
Genetic linkage map: A map of gene positions inferred from recombination frequencies between genetic markers. Linkage maps estimate the relative order and spacing of genes along chromosomes.
Blending inheritance: A historical model proposing that parental traits mix irreversibly in offspring. Discrete chromosome-borne genes preserve hereditary variants rather than blending them away.
Mendelian inheritance: Patterns of inheritance described by Gregor Mendel, including segregation of alleles and independent assortment. Chromosome behavior gives a physical explanation for Mendel’s inheritance patterns.
Walter Sutton: An American geneticist who connected chromosome behavior in meiosis with Mendel’s laws of inheritance. Sutton independently proposed that chromosomes carry hereditary factors.
Chromosome: A DNA molecule packaged with proteins that carries genetic information in cells. Chromosomes are the physical structures the theory identifies as vehicles of inheritance.
Cytogenetics: The study of chromosomes, including their structure, number, behavior, and variation. Cytogenetics examines the chromosome-level changes that alter inheritance.
Pangenesis: A historical hypothesis that particles from body parts collect in reproductive organs and transmit traits. The chromosome theory locates hereditary material in chromosomes rather than throughout the body.

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