Transmission analysis of mitotically unstable B chromosomes in Locusta migratoria

Genome ◽  
1994 ◽  
Vol 37 (6) ◽  
pp. 1027-1034 ◽  
Author(s):  
M. C. Pardo ◽  
M. D. López-León ◽  
J. Cabrero ◽  
J. P. M. Camacho
Keyword(s):  
Germ Line ◽  
Current Knowledge ◽  
Locusta Migratoria ◽  
Sexual Transmission ◽  
Natural Populations ◽  
Meiotic Drive ◽  
B Chromosome ◽  
B Chromosomes ◽  
The Other ◽  
Mitotic Instability

Seventeen controlled crosses in which the mitotically unstable B chromosome of Locusta migratoria was carried by one parent only have provided evidence that B chromosomes are significantly eliminated during sexual transmission in males, at a mean rate that almost counteracts the premeiotic accumulation derived from mitotic instability during germ line development. On the other hand, B chromosomes are significantly accumulated in females, presumably by their preferential migration to the secondary oocyte during the first meiotic division. These results substantially change the current knowledge about this B chromosome system, because the main B accumulation occurs in females and not in males, as was hitherto thought. Furthermore, this case shows that the maintenance of a single B system in natural populations may be the result of many different forces and mechanisms acting for and against B chromosomes.Key words: locust, Locusta migratoria, B chromosomes, accumulation mechanisms, meiotic drive, B elimination, parthenogenesis.

B chromosomes of the grasshopper Heteracris littoralis: meiotic behaviour and endophenotypic effects in both sexes

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 797-801 ◽  
Author(s):  
M. I. Cano ◽  
J. L. Santos
Keyword(s):  
Chiasma Frequency ◽  
Main Type ◽  
Natural Populations ◽  
Meiotic Drive ◽  
B Chromosome ◽  
B Chromosomes ◽  
Female Meiosis ◽  
Accumulation Mechanism ◽  
Cell Variance ◽  
High Level

A main type of a large supernumerary B chromosome has been found in several natural populations of the grasshopper Heteracris littoralis. A study on the geographical distribution of the polymorphism and the meiotic behavior of Bs in both sexes has been carried out with special reference to their effect on two endophenotypic parameters: recombination level and macrospermatid production. Male B bivalents are characterized by a high level of pairing and a strict proximal localization of chiasmata. In the females the B chromosome always divides reductionally at anaphase I indicating the possible existence of an accumulation mechanism based on meiotic drive. There is no effect of Bs on either mean chiasma frequency or between-cell variance in either of the sexes. However, in males a positive correlation between the number of Bs and production of abnormal spermatids (macrospermatids) was found.Key words: B chromosomes, chiasma frequency, female meiosis.

Relationship between mitotic instability and accumulation of B chromosomes in males and females of Locusta migratoria

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 23-29 ◽  
Author(s):  
E. Viseras ◽  
J. P. M. Camacho ◽  
M. I. Cano ◽  
J. L. Santos
Keyword(s):  
Germ Line ◽  
Locusta Migratoria ◽  
B Chromosomes ◽  
Intraindividual Variation ◽  
Mitotic Instability ◽  
Somatic Tissues ◽  
Spanish Populations ◽  
Female Germ Line ◽  
Males And Females ◽  
The Relationship

Mitotic instability of B chromosomes has been studied in males and females from two Spanish populations of Locusta migratoria. This instability is a common feature in embryos, adult somatic tissues such as gastric caeca, and ovariole wall cells and male and female germ lines. While B chromosomes accumulate in the male germ line independently of the existence or absence of intraindividual variation in the number of B chromosomes in gastric caeca cells, they do not accumulate in the female germ line despite meiotic instability. The relationship between the mitotic instability of the B chromosomes in germ lines and their mode of transmission is discussed.Key words: Locusta migratoria, B chromosomes, mitotic instability, accumulation.

Meiotic stability of B chromosomes and production of macrospermatids in Aiolopus strepens (Orthoptera: Acrididae)

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 5-10 ◽  
Author(s):  
J. A. Suja ◽  
C. Garcia de la Vega ◽  
J. S. Rufas
Keyword(s):  
Key Words ◽  
Natural Populations ◽  
B Chromosomes ◽  
Supernumerary Chromosomes ◽  
Mitotic Instability ◽  
Meiotic Stability ◽  
Intercellular Connections

Four males from several Spanish natural populations of Aiolopus strepens were found to carry B chromosomes. These are short and acrocentric and are identical in the different individuals. They show mitotic instability and meiotic stability. When present in odd numbers one unpaired B is generally observed, while in even numbers they usually form bivalents. In no case were lagging B's observed. B chromosomes do not affect nucleolar expression. A significant increase in the number of macrospermatids is found in individuals with B's. This is more pronounced in follicles containing odd numbers of supernumerary chromosomes. A possible explanation based on an assumed influence of B univalents on the maintenance of intercellular connections is discussed. Key words: B chromosomes, spermiogenesis, insect cytogenetics.

scholarly journals The B chromosome of Pseudococcus viburni: a selfish chromosome that exploits whole-genome meiotic drive

2021 ◽  
Author(s):  
Isabelle M. Vea ◽  
Andrés G. de la Filia ◽  
Kamil S. Jaron ◽  
Andrew Joseph Mongue ◽  
Fransico J. Ruiz-Ruano ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Expression Data ◽  
Meiotic Drive ◽  
B Chromosome ◽  
Male Meiosis ◽  
B Chromosomes ◽  
Whole Genome ◽  
Expression Data ◽  
Fair Process ◽  
Pseudococcus Viburni

Meiosis, the key process underlying sexual reproduction, is generally a fair process: each chromosome has a 50% chance of being included into each gamete. However in some organisms meiosis has become highly aberrant with some chromosomes having a higher chance of making it into gametes than others. Yet why and how such systems evolve remains unclear. Here we study the unusual reproductive genetics of mealybugs, in which only maternal-origin chromosomes are included into the gametes during male meiosis, while paternally-derived chromosomes degrade. This whole genome meiotic drive occurs in all males and is evolutionarily conserved. However one species - the obscure mealybug Pseudococcus viburni - has a segregating B chromosome that increases in frequency by escaping paternal genome elimination. Here we present whole-genome and gene expression data from laboratory lines with and without B chromosomes. These data allow us to identify B-linked sequences including >70 protein-coding genes as well as a B-specific satellite repeat that makes up a significant proportion of the chromosome. We also used these data to investigate the evolutionary origin of the B chromosome. The few paralogs between the B and the core genome are distributed throughout the genome, showing that it is unlikely that the B originated through a simple duplication of one of the autosomes. We also find that while many of the B-linked genes do not have paralogs within the P.viburni genome, but they do show orthology with genes in other hemipteran insects suggesting that the B might have originated from fission of one of the autosomes, possibly followed by further translocations of individual genes. Finally in order to understand the mechanisms by which the B is able to escape elimination when paternally-derived we generated gene expression data for males and females with and without B chromosomes. We find that at the developmental stage when meiosis is taking place only a small number of B-linked genes show significant expression. Only one gene was significantly over-expressed during male meiosis, which is when the drive occurs: a acetyltransferase involved in H3K56Ac, which has a putative role in meiosis and is therefore a promising candidate for further studies. Together, these results form a promising foundation for studying the mechanisms of meiotic drive in a system that is uniquely suited for this approach.

scholarly journals B Chromosomes in Free-Living Flatworms of the Genus Macrostomum (Platyhelminthes, Macrostomorpha)

2021 ◽  
Vol 22 (24) ◽  
pp. 13617
Author(s):  
Kira S. Zadesenets ◽  
Nikolay B. Rubtsov
Keyword(s):  
Genome Duplication ◽  
Natural Populations ◽  
B Chromosome ◽  
Laboratory Culture ◽  
B Chromosomes ◽  
Free Living ◽  
Transmission Rates ◽  
Supernumerary Chromosomes

B chromosomes (Bs) or supernumerary chromosomes are extra chromosomes in the species karyotype that can vary in its copy number. Bs are widespread in eukaryotes. Usually, the Bs of specimens collected from natural populations are the object of the B chromosome studies. We applied another approach analyzing the Bs in animals maintained under the laboratory conditions as lines and cultures. In this study, three species of the Macrostomum genus that underwent a recent whole-genome duplication (WGD) were involved. In laboratory lines of M. lignano and M. janickei, the frequency of Bs was less than 1%, while in the laboratory culture of M. mirumnovem, it was nearer 30%. Their number in specimens of the culture varied from 1 to 14. Mosaicism on Bs was discovered in parts of these animals. We analyzed the distribution of Bs among the worms of the laboratory cultures during long-term cultivation, the transmission rates of Bs in the progeny obtained from crosses of worms with different numbers of Bs, and from self-fertilized isolated worms. The DNA content of the Bs in M. mirumnovem was analyzed with the chromosomal in situ suppression (CISS) hybridization of microdissected DNA probes derived from A chromosomes (As). Bs mainly consisted of repetitive DNA. The cytogenetic analysis also revealed the divergence and high variation in large metacentric chromosomes (LMs) containing numerous regions enriched for repeats. The possible mechanisms of the appearance and evolution of Bs and LMs in species of the Macrostomum genus were also discussed.

scholarly journals Changing sex for selfish gain: B chromosomes of Lake Malawi cichlid fish

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Frances E. Clark ◽  
Thomas D. Kocher
Keyword(s):  
Linkage Group ◽  
Transmission Rate ◽  
Cichlid Fish ◽  
Meiotic Drive ◽  
B Chromosome ◽  
Lake Malawi ◽  
B Chromosomes ◽  
Normal Complement ◽  
Biased Sex Ratio ◽  
Average Transmission

AbstractB chromosomes are extra, non-essential chromosomes present in addition to the normal complement of A chromosomes. Many species of cichlid fish in Lake Malawi carry a haploid, female-restricted B chromosome. Here we show that this B chromosome exhibits drive, with an average transmission rate of 70%. The offspring of B-transmitting females exhibit a strongly female-biased sex ratio. Genotyping of these offspring reveals the B chromosome carries a female sex determiner that is epistatically dominant to an XY system on linkage group 7. We suggest that this sex determiner evolved to enhance the meiotic drive of the B chromosome. This is some of the first evidence that female meiotic drive can lead to the invasion of new sex chromosomes solely to benefit the driver, and not to compensate for skewed sex ratios.

scholarly journals Mitotic instability of B chromosomes during embryo development in Locusta migratoria

Heredity ◽  
1995 ◽  
Vol 74 (2) ◽  
pp. 164-169 ◽  
Author(s):  
M C Pardo ◽  
M D Lopez-Leon ◽  
E Viseras ◽  
J Cabrero ◽  
J P M Camacho
Keyword(s):  
Embryo Development ◽  
Locusta Migratoria ◽  
B Chromosomes ◽  
Mitotic Instability

GENOTYPES SUPPRESSING MEIOTIC DRIVE OF A B CHROMOSOME IN THE MEALYBUG, PSEUDOCOCCUS OBSCURUS

Genetics ◽  
1985 ◽  
Vol 110 (1) ◽  
pp. 73-92 ◽  
Author(s):  
Uzi Nur ◽  
Betty Lou H Brett
Keyword(s):  
Genetic Factors ◽  
Female Parent ◽  
Meiotic Drive ◽  
B Chromosome ◽  
B Chromosomes ◽  
Isofemale Line ◽  
Maternal Origin ◽  
Isofemale Lines ◽  
Rapid Loss

ABSTRACT The rate of transmission (k) of a supernumerary B chromosome in male mealybugs is shown to depend strongly on the chromosome set of maternal origin. When both parents came from an isofemale line in which the frequency of the B chromosome increased rapidly and stabilized at a mean of more than 4.0 B chromosomes per individual, k was 0.92 and 0.95 in two series of crosses. However, when the female parent came from one of two isofemale lines in which the frequency of the B chromosome decreased from 2.0 to 0 in a few generations, k ranged from 0.53 to 0.78. The high ks, which represent a strong meiotic drive, are apparently responsible for the observed increase in the frequency of the B chromosome in several lines from a mean of about 0.5 to more than 4.0 in about 20 generations. The rapid loss of the B chromosome in other lines is attributed to genetic factors which caused the reduction in the rate of transmission of the B chromosome.

Sign in / Sign up

Export Citation Format

Share Document