Video Experimental Relacionado
Updated: Jul 8, 2026
06:22
Mass-Rearing and Molecular Studies in Tortricidae Pest Insects
Published on: March 25, 2022
La rareza de los machos en los áfidos de guisante resulta en una desintegración mutacional
Jennifer A Brisson1, Sergey V Nuzhdin
1Section of Ecology and Evolution, University of California, Davis, CA 95616, USA. jabrisson@ucdavis.edu
Science (New York, N.Y.)
|January 5, 2008
Resumen
En los pulgones, la reproducción asexual por las hembras conduce al debilitamiento evolutivo de los machos. Los genes orientados al sexo masculino muestran una evolución acelerada y mayores tasas de mutación, lo que sugiere una descomposición genética en el sexo menos seleccionado.
Área de la Ciencia:
- Biología evolutiva Biología evolutiva.
- Genética La genética.
- Estrategias reproductivas estrategias reproductivas.
Sus antecedentes:
- La reproducción sexual es común, pero algunas especies exhiben reproducción asexual facultativa u obligatoria.
- Las implicaciones evolutivas para el sexo "más débil" en especies con reproducción sexual reducida no se comprenden completamente.
- Los áfidos proporcionan un sistema modelo único con generaciones asexuales y sexuales alternadas.
Objetivo del estudio:
- Investigar si los machos se convierten en un sexo evolutivamente más débil en especies donde las hembras pueden reproducirse asexualmente.
- Determinar si los genes específicos masculinos experimentan desintegración mutacional cuando la reproducción sexual es infrecuente.
- Para probar la hipótesis de reducción de las restricciones de selección en los genes masculinos sesgados en los áfidos.
Principales métodos:
- Se emplearon análisis de microarrays para identificar sesgos de expresión génica (sesgo masculino, sesgo femenino, neutral).
- Se utilizaron comparaciones interespecíficas para evaluar las tasas de evolución molecular.
- Se analizaron datos de polimorfismo intraspecífico para detectar patrones de variación genética.
Principales resultados:
- Los genes con sesgo masculino mostraron una evolución acelerada en comparación con otros tipos de genes.
- Se observó un exceso significativo de variación de codificación no sinónima en los genes sesgados masculinos dentro de las especies.
- Estos hallazgos sugieren una reducción de la selección purificadora en los genes relacionados con los machos.
Conclusiones:
- La capacidad de reproducción asexual en los áfidos femeninos reduce las presiones de selección sobre los genes asociados al macho.
- Esta relajación de la selección conduce a la descomposición mutacional y la evolución acelerada en los genes con sesgo masculino.
- Los machos pueden representar un sexo evolutivamente "más débil" en sistemas con reproducción asexual frecuente.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:41Lethal Alleles
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...
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
01:19X-linked Traits
In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be masked by the presence of a normal allele on the second X. In contrast, a mutation on the X chromosome in males more often causes observable biological defects, as there is no normal X to compensate. Trait variations arising from mutations on the X chromosome are called “X-linked”.
01:49Hardy-Weinberg Principle
Diploid organisms have two alleles of each gene, one from each parent, in their somatic cells. Therefore, each individual contributes two alleles to the gene pool of the population. The gene pool of a population is the sum of every allele of all genes within that population and has some degree of variation. Genetic variation is typically expressed as a relative frequency, which is the percentage of the total population that has a given allele, genotype or phenotype.In the early 20th century,...
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.
01:09Mutation, Gene Flow, and Genetic Drift
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).Mechanisms of Genetic VariationThe original sources of genetic variation are mutations,...