Related Concept Videos
01:27Disorders of Leukocytes
2.2K
Leukocyte disorders can lead to either leukopenia, characterized by an abnormally low leukocyte count, or leukocytosis, marked by a very high leukocyte number.
Leukopenia may result from bone marrow disorders, autoimmune diseases, and infectious diseases. For example, conditions such as multiple myeloma and aplastic anemia can impair the bone marrow's ability to produce adequate leukocytes. Similarly, autoimmune diseases like lupus and viral infections such as HIV can prompt the immune...
Leukopenia may result from bone marrow disorders, autoimmune diseases, and infectious diseases. For example, conditions such as multiple myeloma and aplastic anemia can impair the bone marrow's ability to produce adequate leukocytes. Similarly, autoimmune diseases like lupus and viral infections such as HIV can prompt the immune...
2.2K
01:20Monohybrid Crosses
240.1K
Overview
240.1K
01:39Epistasis
50.6K
In addition to multiple alleles at the same locus influencing traits, numerous genes or alleles at different locations may interact and influence phenotypes in a phenomenon called epistasis. For example, rabbit fur can be black or brown depending on whether the animal is homozygous dominant or heterozygous at a TYRP1 locus. However, if the rabbit is also homozygous recessive at a locus on the tyrosinase gene (TYR), it will have an unshaded coat that appears white, regardless of its TYRP1...
50.6K
01:43Incomplete Dominance
30.8K
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.
30.8K
01:49Law of Segregation
78.6K
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.
78.6K
02:41Lethal Alleles
18.5K
Agouti: A Lethal Allele
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
18.5K
You might also read
Related Articles
Articles linked to this work by shared authors, journal, and citation graph.
Sort by
Same author
Avian mortality at oil pits in the United States: A review of the problem and efforts for its solution.
Environmental management·2006
Related Experiment Video
Updated: Mar 1, 2026
12:04
The bm12 Inducible Model of Systemic Lupus Erythematosus SLE in C57BL/6 Mice
Published on: November 1, 2015
18.8K
WHY SHOULD LEK-BREEDERS BE MONOMORPHIC?
1Department of Ornithology and Mammalogy, California Academy of Sciences, San Francisco, CA, 94118, USA.
Summary
Sexual monomorphism in lek-breeding birds like the capuchinbird may stem from intense social competition impacting both sexes. This competition drives plumage evolution, leading to shared exaggerated traits in males and females.
Area of Science:
- Ornithology
- Behavioral Ecology
- Evolutionary Biology
Background:
- Approximately 25% of lek-breeding bird species exhibit sexual monomorphism, deviating from the typical correlation between sexual selection and sexual dimorphism.
- Understanding the evolutionary significance of monomorphism requires detailed data on the mating systems of both monomorphic and dimorphic species.
Purpose of the Study:
- To investigate the social and sexual behavior of the sexually monomorphic capuchinbird (Perissocephalus tricolor).
- To compare the mating system of the capuchinbird with the sexually dimorphic Guianan cock-of-the-rock (Rupicola rupicola), both lek-breeding species in the cotinga family.
Main Methods:
- Observational study of the social and sexual behavior of capuchinbirds at leks.
- Comparative analysis of mating systems between capuchinbirds and Guianan cocks-of-the-rock.
Main Results:
- Male capuchinbirds engaged in direct dominance contests for prime display sites, with one dominant male monopolizing copulations.
- Both male and female capuchinbirds exhibited intense aggression at leks, and both sexes participated in sexual mimicry.
- In contrast, dimorphic lek birds typically engage in territorial displays rather than direct dominance contests.
Conclusions:
- Social competition, affecting both sexes, is proposed as a driving force behind plumage monomorphism in lek birds.
- This hypothesis explains the exaggerated, shared plumage characteristics observed in capuchinbirds and other monomorphic lek species.
- Plumage evolution in these species can be viewed as an evolutionary arms race, with varying selective forces leading to different states of sexual dimorphism or indistinguishability.