scholarly journals CROSSING OVER IN THE SEX CHROMOSOME OF RACIAL HYBRIDS OF DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1937 ◽  
Vol 22 (2) ◽  
pp. 249-256
Author(s):  
R H MacKnight
Keyword(s):  
Sex Chromosome ◽  
Drosophila Pseudoobscura ◽  
Crossing Over ◽  
Racial Hybrids

scholarly journals CROSSING-OVER IN THE SEX CHROMOSOME OF THE MALE FOWL

Science ◽  
1917 ◽  
Vol 46 (1183) ◽  
pp. 213-213 ◽  
Author(s):  
H. D. Goodale
Keyword(s):  
Sex Chromosome ◽  
Crossing Over

scholarly journals THE GENOTYPIC CONTROL OF CROSSING OVER IN DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1954 ◽  
Vol 39 (5) ◽  
pp. 677-691
Author(s):  
Robert Paul Levine ◽  
Elizabeth Epling Levine
Keyword(s):  
Drosophila Pseudoobscura ◽  
Crossing Over ◽  
Genotypic Control

scholarly journals VARIABLE CROSSING OVER ARISING IN DIFFERENT STRAINS OF DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1955 ◽  
Vol 40 (3) ◽  
pp. 399-405
Author(s):  
R P Levine ◽  
Elizabeth E Levine
Keyword(s):  
Drosophila Pseudoobscura ◽  
Crossing Over ◽  
Different Strains

scholarly journals Sex ratios in natural populations of Drosophila pseudoobscura from Mexico

Genetika ◽  
2012 ◽  
Vol 44 (3) ◽  
pp. 491-498 ◽  
Author(s):  
Victor Salceda ◽  
Carolina Arceo-Maldonado
Keyword(s):  
Sex Ratio ◽  
Sex Chromosome ◽  
Natural Populations ◽  
Diploid Species ◽  
Drosophila Pseudoobscura ◽  
Adult Offspring ◽  
Equal Proportion ◽  
X Chromosomes ◽  
The Individual ◽  
Number Of Males

Most species show an equal proportion of individuals of both sexes. In diploid species sex ratio is determined by a genic balance between sex chromosomes. In Drosophila sex is determined by the ratio of X- chromosomes versus autosomes and in some species of the genus it is related to the presence of an inversion in the sex chromosome. The present work analyses the sex ratio in 27 natural populations of Drosophila pseudoobscura that inhabit Mexico. Female flies captured in nature were counted and their sex ratio calculated and been called generation P, then cultured individualy, allowed to leave adult offspring which was quantified in order to get its sex ratio and designated generation F1. sex ratio was calculated using the expression: number of males times 100 divided by the number of females proposed by Darwin (1871). The sex ratio of each population was taken using the average of all the individual counts from each sample. The values found varied among different generations and populations, so for generation P their values varieded 37.4 to 190.4 and in generation F1 from 31.3 up to 96.4 males for each 100 females. According to their geographical distribution four North to South transects were arranged and in them means varied from 60.8 to 81.7 males for each 100 females. All this means that in Mexican population are more females than males, exceptionally more males than females.

scholarly journals Temperature related fertility selection on body size and the sex-ratio gene arrangement in Drosophila pseudoobscura

1993 ◽  
Vol 62 (1) ◽  
pp. 63-75 ◽  
Author(s):  
M. D. Gebhardt ◽  
W. W. Anderson
Keyword(s):  
Body Size ◽  
Sex Chromosome ◽  
Gene Arrangement ◽  
Drosophila Pseudoobscura ◽  
Measured Temperature ◽  
Low Frequencies ◽  
Higher Temperature ◽  
Phenotypic Fitness ◽  
Lower Temperature ◽  
Fertility Selection

SummaryWe measured temperature-dependent fertility selection on body size in Drosophila pseudoobscura in the laboratory. One hundred single females of each of the three karyotypes involving the ‘sexratio’ (SR) and the standard (ST) gene arrangement on the sex chromosome laid eggs at either 18 or 24°C. The experiment addressed the following hypotheses: (a) Fertility selection on body size is weaker at the higher temperature, explaining in part why genetically smaller flies appear to evolve in populations at warmer localities, (b) Homokaryotypic SR females are less fecund than homokaryotypic ST females, possibly mediated by the effect of body size on fertility, explaining the low frequencies of SR despite its strong advantage due to meiotic drive. The data were also expected to shed light on a mechanism for the evolution of plasticity of body size through fertility selection in environments with an unpredictable temperature regime. Hypothesis (a) was clearly refuted because phenotypically larger ST females had an even larger fertility surplus at the higher temperature and, more importantly, the genetic correlation between fertility and body size disappeared at the lower temperature. As to (b), we found that temperature affects fertility directly and indirectly through body size such that ST and SR females were about equally fecund at both temperatures, although different in size and size-adjusted fertility. We observed heterosis for both size and fertility, which might stabilize the polymorphism in nature. The reaction norms of body size to the temperature difference were steeper for ST females than for SR females, implying that fertility selection could change phenotypic plasticity of body size in a population. Selection on body size depended not only on the temperature, but also on the karyotypes, suggesting that models of phenotype evolution using purely phenotypic fitness functions may often be inadequate.

scholarly journals Novitski’s Distal shift in Paracentric Inversion Evolution

2018 ◽  
Author(s):  
Spencer A. Koury
Keyword(s):  
Chromosome Evolution ◽  
Meiotic Drive ◽  
Distinct Pattern ◽  
Paracentric Inversion ◽  
Drosophila Pseudoobscura ◽  
Crossing Over ◽  
Female Meiosis ◽  
Chromosomal Inversions ◽  
Underlying Principle

AbstractIn Drosophila pseudoobscura younger chromosomal inversions tend to be found distal to older inversions. By examining phylogenetic series of overlapping inversions for 134 gene arrangements of 13 chromosomes this pattern was extended to five additional Drosophila species. This distinct pattern arose repeatedly and independently in all six species and likely reflects an underlying principle of chromosome evolution. In this study it is illustrated how transmission of distal inversions is always favored in female meiosis when crossing over in homosequential regions of overlapping inversions generates asymmetric dyads. This cytogenetic mechanism for female meiotic drive is described in detail and advanced as an explanation for the distal shift in phylogenetic series of overlapping inversions as well as several better known patterns in the evolution of serially inverted chromosomes.

GLUTAMATE-OXALOACÉTATE TRANSAMINASE ET α-GLYCÉROPHOSPHATE DÉSHYDROGÉNASE CHEZ LE MOUSTIQUE AEDES (OCHLEROTATUS) CASPIUS: GÉNÉITIQUE FORMELLE ET ÉTUDE DE POPULATIONS

1979 ◽  
Vol 21 (1) ◽  
pp. 25-32 ◽  
Author(s):  
André Mery ◽  
Nicole Pasteur ◽  
Eliane Guilvard
Keyword(s):  
Electrophoretic Mobility ◽  
Sibling Species ◽  
Sex Chromosome ◽  
Crossing Over ◽  
Glutamate Oxaloacetate Transaminase ◽  
Low Level ◽  
Aedes Caspius ◽  
Glycerophosphate Dehydrogenase

In Aedes caspius (Pallas) the α-Gpd locus, coding an α-glycerophosphate dehydrogenase, has three codominant alleles and is localized on the sex chromosome at about one unit of crossing-over from the sex factor. The Got-1 locus, coding a glutamate-oxaloacetate transaminase has four codominant alleles and is autosomal. The study of nine populations collected in France, Tunisia and Morocco demonstrates a low level of polymorphism at the α-Gpd locus (heterozygosity of 0.065 per population) and a high polymorphism at the Got-1 locus (heterozygosity of 0.496 per population). Got-1 polymorphism of A. caspius is compared with that of the two A. detritus sibling species that segregate for alleles with the same electrophoretic mobility, and colonized the same sites.

VII.—Spermatogenesis in Drosophila pseudo-obscura Frolowa. II. The Cytological Basis of Sterility in Hybrid Males of Races A and B

1935 ◽  
Vol 54 ◽  
pp. 67-87 ◽  
Author(s):  
P. Ch. Koller
Keyword(s):  
Sex Chromosome ◽  
Present Writer ◽  
Crossing Over

Two races or physiological species (A and B) were found in Drosophila pseudo-obscura by Lancefield (1922), who described later (1925, 1929) the genetical behaviour of the interracial hybrids. The present writer (1931, 1932, a, b) has reported further investigations concerning the sterility of the male and the regional reduction of crossing-over in the female of the interracial hybrids. The results obtained suggested that there are genetic fertility factors, located in the sex chromosome complex, which are primarily responsible for the sterility of the F1 males. A similar conclusion has been reached more recently by Dobzhansky (1933 b) from his cytological studies of hybrid males.

scholarly journals Is the Rate of Insertion and Deletion Mutation Male Biased?: Molecular Evolutionary Analysis of Avian and Primate Sex Chromosome Sequences

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 259-268
Author(s):  
Hannah Sundström ◽  
Matthew T Webster ◽  
Hans Ellegren
Keyword(s):  
Dna Sequences ◽  
Large Scale ◽  
Sex Chromosome ◽  
Z Chromosome ◽  
Crossing Over ◽  
Evolutionary Analysis ◽  
W Chromosome ◽  
Insertion And Deletion ◽  
Indel Mutation ◽  
Molecular Evolutionary Analysis

Abstract The rate of mutation for nucleotide substitution is generally higher among males than among females, likely owing to the larger number of DNA replications in spermatogenesis than in oogenesis. For insertion and deletion (indel) mutations, data from a few human genetic disease loci indicate that the two sexes may mutate at similar rates, possibly because such mutations arise in connection with meiotic crossing over. To address origin- and sex-specific rates of indel mutation we have conducted the first large-scale molecular evolutionary analysis of indels in noncoding DNA sequences from sex chromosomes. The rates are similar on the X and Y chromosomes of primates but about twice as high on the avian Z chromosome as on the W chromosome. The fact that indels are not uncommon on the nonrecombining Y and W chromosomes excludes meiotic crossing over as the main cause of indel mutation. On the other hand, the similar rates on X and Y indicate that the number of DNA replications (higher for Y than for X) is also not the main factor. Our observations are therefore consistent with a role of both DNA replication and recombination in the generation of short insertion and deletion mutations. A significant excess of deletion compared to insertion events is observed on the avian W chromosome, consistent with gradual DNA loss on a nonrecombining chromosome.

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