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Updated: May 27, 2026
07:54
Manipulation of Ploidy in Caenorhabditis elegans
Published on: March 15, 2018
Haploid embryonic stem cells and the dominance of recessive traits
1Center for Vertebrate Genomics, Cornell University, Ithaca, NY 14850, USA. jcs92@cornell.edu
Cell Stem Cell
|December 6, 2011
Abstract:
Diploidy, though essential for normal development, is a foil to geneticists. Two recent studies (Elling et al., 2011, this issue of Cell Stem Cell; Leeb and Wutz, 2011, Nature), report the isolation of haploid pluripotent mouse ESCs, thus enabling efficient functional screening for genes involved in diverse cellular and developmental processes.
Related Concept Videos
01:35Pedigree Analysis
Overview
01:43Incomplete Dominance
Gregor Mendel's work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid cell has two variants called alleles inherited from each parent. He suggested that amongst these two alleles, one allele is dominant in character and the other recessive. The combination of alleles determines the phenotype of a gene in an organism.
01:49Law 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 generation, and could reappear in the next generation (F2). He concluded that one of the traits must be dominant over the other, thereby causing masking of one trait in the F1 generation. When he crossed the F1 plants, he found that 75% of the offspring in the F2 generation had the dominant phenotype, while 25% had the recessive phenotype.
01:39Test Cross
Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.
01:11Genetic Lingo
Overview
02:03Law of Independent Assortment
While Mendel’s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how different genes are inherited remains. For example, is the gene for tall plants inherited with the gene for green peas? Mendel asked this question by experimenting with a dihybrid cross; a cross in which both parents are homozygous for two distinct traits resulting in an F1 generation that are heterozygous for both traits.