scholarly journals ENZYMES AND REPRODUCTION IN NATURAL POPULATIONS OF DROSOPHILA EURONOTUS

Genetics ◽  
1976 ◽  
Vol 84 (2) ◽  
pp. 375-384
Author(s):  
Harrison D Stalker
Keyword(s):  
Sexual Maturity ◽  
Multiple Mating ◽  
Natural Populations ◽  
Allele Frequencies ◽  
Laboratory Studies ◽  
Enzyme Locus ◽  
Chromosomal Locus ◽  
Large Numbers ◽  
True Frequency ◽  
Two Populations

ABSTRACT Populations of Drosophila euronotus, one from southern Louisiana (3 samples), and one from Missouri (2 samples), were classified for allele frequencies at alkaline phosphatase (APH) and acid phosphatase (ACPH) loci. The two populations differed consistently in allele frequencies at both loci. The APH locus is on the inversion-free X chromosome; the chromosomal locus of the autosomal ACPH is unknown, and could involve inversion polymorphism. Wild females from Missouri and Louisiana populations heterozygous at the APH locus carried more sperm at capture than did the corresponding homozygotes. This heterotic association was significant for the combined samples, and whether it was the result of heterosis at the enzyme locus studied, or due to geographically widespread close linkage with other heterotic loci, it should help to maintain heterozygosity at the APH locus. In a Louisiana collection which included large numbers of sperm-free females, simultaneous homozygosity at both enzyme loci was significantly associated with lack of sperm. It is suggested that the latter association is the result of young heterozygous females achieving sexual maturity earlier than do the double homozygotes. The average effective sperm load for 225 wild females was only 29.4, suggesting the necessity for frequent repeat-mating in nature to maintain female fertility. A comparison of the sex-linked APH genotypes of wild females with those of their daughters indicated that among 295 wild-inseminated females from five populations, 35% had mated more than once, and of this 35%, six females had mated at least three times. Because of ascertainment difficulties, it is clear that the true frequency of multiple-mating in nature must have been much higher than the observed 35%. Laboratory studies indicate that multiple-mating in this species does not involve sperm displacement, possibly due to the small number of sperms transmitted per mating, and the fact that the sperm receptacles are only partially filled by a given mating.

scholarly journals NULL ALLELE FREQUENCIES AT ALLOZYME LOCI IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 99 (1) ◽  
pp. 151-156
Author(s):  
Charles H Langley ◽  
Robert A Voelker ◽  
Andrew J Leigh Brown ◽  
Seido Ohnishi ◽  
Barbara Dickson ◽  
...  
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Natural Populations ◽  
Allele Frequencies ◽  
Null Alleles ◽  
Carolina Population ◽  
The Mean ◽  
Allozyme Loci ◽  
Two Populations

ABSTRACT We have sampled a London population of Drosophila melanogaster for null alleles at twenty-five allozyme loci. The same loci and biochemical techniques were used as in our previous survey of a North Carolina population (Voelker et al. 1980). This second survey is completely concordant with the first. No nulls were detected among the five X-linked loci. The mean frequency of nulls at the twenty autosomal loci was 0.0023. Although there is significant interlocus heterogeneity, the two populations appear to have the same frequencies at each locus. This suggests that null alleles at these allozyme loci are in mutation-selection balance, and we estimate the average heterozygous effect of an allozyme null to be 0.0015. Consideration of allozyme null-allele frequencies, the effects of allozyme null alleles on viability and fertility and the generally greater amount of genetic variability at allozyme loci determined by electrophoresis lead us to doubt the validity of generalizing from allozyme data to the whole genome.

Sex ratio and life history traits at reaching sexual maturity in the dioecious shrub Fuchsia parviflora: field and common garden experiments

2021 ◽  
pp. 1-6
Author(s):  
Jessica S. Ambriz ◽  
Clementina González ◽  
Eduardo Cuevas
Keyword(s):  
Natural Population ◽  
Sexual Maturity ◽  
Sex Ratios ◽  
Natural Populations ◽  
Common Garden ◽  
Common Garden Experiment ◽  
Trade Offs ◽  
Reproductive Biomass ◽  
Common Garden Experiments ◽  
Growth And Reproduction

Abstract Fuchsia parviflora is a dioecious shrub that depends on biotic pollination for reproduction. Previous studies suggest that the male plants produce more flowers, and male-biased sex ratios have been found in some natural populations. To assess whether the biased sex ratios found between genders in natural populations are present at the point at which plants reach sexual maturity, and to identify possible trade-offs between growth and reproduction, we performed a common garden experiment. Finally, to complement the information of the common garden experiment, we estimated the reproductive biomass allocation between genders in one natural population. Sex ratios at reaching sexual maturity in F. parviflora did not differ from 0.5, except in one population, which was the smallest seedling population. We found no differences between genders in terms of the probability of germination or flowering. When flowering began, female plants were taller than males and the tallest plants of both genders required more time to reach sexual maturity. Males produced significantly more flowers than females, and the number of flowers increased with plant height in both genders. Finally, in the natural population studied, the investment in reproductive biomass was seven-fold greater in female plants than in male plants. Our results showed no evidence of possible trade-offs between growth and reproduction. Despite the fact that female plants invest more in reproductive biomass, they were taller than the males after flowering, possibly at the expense of herbivory defence.

The origin of multiple mating types in mushrooms

1993 ◽  
Vol 104 (2) ◽  
pp. 227-230
Author(s):  
U. Kues ◽  
L.A. Casselton
Keyword(s):  
Mating Type ◽  
Multiple Mating ◽  
Mating Types ◽  
Mating Partner ◽  
Binucleate Cells ◽  
Large Numbers ◽  
Mating Type Genes ◽  
And Function ◽  
Developmental Switch ◽  
Sterile Mycelium

Having multiple mating types greatly improves the chances of meeting a compatible mating partner, particularly in an organism like the mushroom that has no sexual differentiation and no mechanism for signalling to a likely mate. Having several thousands of mating types, as some mushrooms do, is, however, remarkable - and even more remarkable is the fact that individuals only recognise that they have met a compatible mate after their cells have fused. How are such large numbers of mating types generated and what is the nature of the intracellular interaction that distinguishes self from non- self? Answers to these fascinating questions come from cloning some of the mating type genes of the ink cap mushroom Coprinus cinereus. A successful mating in Coprinus triggers a major switch in cell type, the conversion of a sterile mycelium with uninucleate cells (monokaryon) to a fertile mycelium with binucleate cells (dikaryon) which differentiates the characteristic fruit bodies. The mating type genes that regulate this developmental switch map to two multiallelic loci designated A and B and these must both carry different alleles for full mating compatibility. A and B independently regulate different steps in the developmental switch, making it possible to study just one component of the system and work in our laboratory has concentrated on understanding the structure and function of the A genes. It is estimated that some 160 different A mating types exist in nature, any two of which can together trigger the A-regulated part of sexual development. The first clue to how such large numbers are generated came from classical genetic analysis, which identified two functionally redundant A loci, (alpha) and beta. Functional redundancy is, indeed, the key to multiple A mating types and, as seen in Fig.1, molecular cloning has identified many more genes than was possible by recombination analysis.

Evidence for multiple paternity in two species of Orconectes crayfish

2014 ◽  
Vol 92 (11) ◽  
pp. 985-988 ◽  
Author(s):  
A.F. Kahrl ◽  
R.H. Laushman ◽  
A.J. Roles
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Multiple Mating ◽  
Natural Populations ◽  
Multiple Paternity ◽  
The Body ◽  
Freshwater Crayfish ◽  
Decapod Crustaceans ◽  
Freshwater Habitats ◽  
Crayfish Species

Multiple mating is expected to be common in organisms that produce large clutches as a mechanism by which sexual reproduction can enrich genetic variation. For freshwater crayfish, observation of multiple mating suggests the potential for high rates of multiple paternity, but genetic confirmation is largely lacking from natural populations. We studied paternity within wild-caught broods of two crayfish species in the genus Orconectes (Sanborn’s crayfish (Orconectes sanbornii (Faxon, 1884)) and the Allegheny crayfish (Orconectes obscurus (Hagen, 1870))). Although females have been observed mating with multiple males, this is the first genetic confirmation of multiple paternity in broods of these two species. Berried females were collected in the field and maintained in aquaria until their eggs hatched. We amplified and genotyped extracted DNA from maternal and hatchling tissue for several microsatellite loci. For both species, paternity reconstruction (GERUD 2.0) yielded 2–3 sires per brood and no single paternity clutches. We discuss these results from natural populations in light of the body of work on reproductive ecology of decapod crustaceans and in the context of changes in life history following the transition from marine to freshwater habitats.

Comparison of allele frequencies of 15 STR loci between two populations in Greece

2012 ◽  
Vol 211 ◽  
pp. S45
Author(s):  
Elena Vakonaki ◽  
Leda Kovatsi ◽  
Athanasios Alegakis ◽  
Vasilis Androutsopoulos ◽  
Miriana Gubandru ◽  
...  
Keyword(s):  
Allele Frequencies ◽  
Str Loci ◽  
Two Populations

scholarly journals Contributions to the biology of the mackerel, Scomber scombrus L. III. Age and growth

1952 ◽  
Vol 30 (3) ◽  
pp. 549-569 ◽  
Author(s):  
G. A. Steven
Keyword(s):  
Sexual Maturity ◽  
Age Groups ◽  
Age And Growth ◽  
Small Fish ◽  
Massachusetts Bay ◽  
Scomber Scombrus ◽  
Bay Area ◽  
Large Numbers ◽  
The Common ◽  
Young Of The Year

The first serious attempt to determine the age and growth rate of the common mackerel (Scomber scombrus L.) appears to have been made by Captain Atwood in 1856 (quoted by Brown Goode, 1884, p. 116) in the Massachusetts Bay area of northern North America. Small fish caught by Atwood in October of that year measuring 6½–7 in. in length (16.5–17.5 cm.) he believed to be the young of the year (i.e. they belonged to the O-group). Mackerel belonging to this group he calls ‘spikes’. ‘Blinks', ‘tinkers’ and ‘second size’ fish he assigns to the I-, II- and III-year age groups respectively, but unfortunately gives no data as to the sizes of those categories, merely stating that everyone well acquainted with mackerel makes the same groupings ‘as there seems to be a line of demarkation between the different kinds which stands out prominently’. Sixteen years later, on 27 July 1872, Malm (1877, p. 409) observed large numbers of small mackerel close inshore in the Gullmarfjord near Christineberg. Several tons of those mackerel were enclosed in a seine, but only ten specimens were retained as all the others escaped through the meshes. These ten fish ranged in length from 67 to 100 mm. and Malm surmised their age to be 13 months. Collett (1880, p. 18) stated that on the coast of Norway I-year-old mackerel are ‘fingerlang’. To fish of 20 cm., taken at the end of August, he ascribed (without supporting data) an age of 2 years, with sexual maturity supervening at 3 years at an unspecified length.

scholarly journals Differences in allele frequencies of Aat between high- and mid-rocky shore populations of Littorina saxatilis (Olivi) suggest selection in this enzyme locus

1989 ◽  
Vol 54 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Kerstin Johannesson ◽  
Bo Johannesson
Keyword(s):  
Aspartate Aminotransferase ◽  
Rocky Shore ◽  
Western Europe ◽  
Allele Frequencies ◽  
Clinal Variation ◽  
Littorina Saxatilis ◽  
Enzyme Locus ◽  
Geographic Locations ◽  
Polymorphic Loci ◽  
Slow Allele

SummarySamples of the intertidal prosobranch Littorina saxatilis were collected along vertical transects from high- to mid-store levels at five different geographic locations of western Europe. Electrophoretic screening of ten metabolic enzymes revealed five highly polymorphic loci. Four of these showed no or few significant differences in allele frequencies between high- and mid-shore samples of Littorina saxatilis. The fifth locus, Aat (aspartate aminotransferase, EC 2.6.1.1), showed clinal variation in allele frequencies over the few metres of each transect, suggesting that this locus, or a coupled locus, is under selection with a slow allele (Aat100) favoured in mid-shore habitats and a faster allele (Aat120) selected for in the high littoral fringe.

Field trials of Trichomalopsis sarcophagae (Hymenoptera: Pteromalidae) in cattle feedlots: a potential biocontrol agent of filth flies (Diptera: Muscidae)

2003 ◽  
Vol 135 (4) ◽  
pp. 599-608 ◽  
Author(s):  
K.D. Floate
Keyword(s):  
Biocontrol Agent ◽  
Natural Populations ◽  
Fold Increase ◽  
Mass Rearing ◽  
Field Trials ◽  
House Fly ◽  
Stable Fly ◽  
Large Numbers ◽  
Potential Biocontrol Agent ◽  
Paired Control

AbstractA field study was performed in southern Alberta, Canada, to assess the native wasp, Trichomalopsis sarcophagae (Gahan), as a potential biocontrol agent for house fly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.). The wasp was readily reared in large numbers, which allowed for the cumulative release of an estimated 4.63 million wasps into three commercial feedlots during the 2-year study. Each of several releases predictably and repeatedly enhanced parasitism of sentinel house fly pupae, whereas parasitism remained low in three paired control feedlots where wasps were not released. Releases every 2nd week had a disproportionately greater effect than releases every 2nd month. In 1998, 1.2 million wasps were released into treatment feedlots resulting in the recovery of 3 952 T. sarcophagae from 31 500 sentinel pupae (0.13 wasps/pupa). In 1999, 3.43 million wasps were released into treatment feedlots, with the recovery of 37 763 wasps from 47 720 sentinel pupae (0.79 wasps/pupa). Hence, a 2.8-fold increase in the number of wasps released in 1999 resulted in a 6.1-fold increase in the recovery of wasps. This result supports industry recommendations of regular, repeated releases of wasps every 2nd or 4th week versus one or infrequent releases throughout the summer. There was no evidence that releases augmented overwintering populations of the wasp in subsequent years. These results provide proof-of-concept for the mass-rearing and release of T. sarcophagae as an inundative biocontrol agent for the control of pest flies in cattle confinements. Further studies will be required to assess the effect of T. sarcophagae releases on natural populations of pest flies.

Variation in cone morphology and seed characters in Pinus strobus in Quebec

1995 ◽  
Vol 73 (2) ◽  
pp. 262-271 ◽  
Author(s):  
Jean Beaulieu ◽  
Jean-Pierre Simon
Keyword(s):  
Natural Populations ◽  
Pinus Strobus ◽  
White Pine ◽  
Ottawa River ◽  
River Region ◽  
Natural Range ◽  
Anticosti Island ◽  
Genotypic Control ◽  
Two Populations ◽  
Cone Scale

To investigate the patterns of variation in white pine (Pinus strobus L.), 10 natural populations from Quebec were compared using the phenotypic variation of cone and seed traits. Eight characters were measured on 10 cones collected from 30 trees in each of the 10 sampled populations. Four populations were from the Ottawa River region and four from the St. Lawrence Lowlands region, while two populations were at the margin of the natural range of the species in Quebec, from the Abitibi region and Anticosti Island. Significant differences among populations were detected for each character. Estimates of repeatability of these traits were relatively high, suggesting substantial genotypic control over them. These estimates were consistent from population to population. Results of multivariate analyses suggest that populations from the Ottawa River region are similar to those from the St. Lawrence region, with populations from these regions diverging only in cone scale length. However, populations from the St. Lawrence region were more distinct from each other than those from the Ottawa River region. The population from Abitibi deviates considerably from the other populations, suggesting habitat-selection pressures acting at the margin of the natural range of the species under continental conditions. Finally, no general geographical trend was detected in the observed variation. Key words: white pine, morphology, cone, seed, variation.

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