John Belote | Syracuse University (original) (raw)
Papers by John Belote
Ecology and Evolution, 2013
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when sele... more Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer the mode of past selection on them. The use of transgenic populations of Drosophila melanogaster with red or green fluorescent-tagged sperm heads permitted in vivo discrimination of sperm from competing males and quantification of characteristics of ejaculate composition, performance, and fate. We found that male attractiveness (mating latency) and competitive fertilization success (P2) both show some inbreeding depression, suggesting they may have been under directional selection, whereas sperm length showed no inbreeding depression suggesting a history of stabilizing selection. However, despite having measured several sperm quality and quantity traits, our data did not allow us to discern the mechanism underlying the lowered competitive fertilization success of inbred (f = 0.50) males.
Nucleic Acids Research, 1998
PCAF and hGCN5 are distinct human genes that encode proteins related to the yeast histone acetylt... more PCAF and hGCN5 are distinct human genes that encode proteins related to the yeast histone acetyltransferase and transcriptional adapter GCN5. The PCAF protein shares extensive similarity with the 439 amino acids of yGCN5, but it has an ~350 amino acid N-terminal extension that interacts with the transcriptional co-acti- vator p300/CBP. Adenoviral protein E1a can disrupt PCAF-CBP interactions and prevent PCAF-dependent
The 73AD salivary chromosome region of Drosophila melanogaster was subjected to mutational analys... more The 73AD salivary chromosome region of Drosophila melanogaster was subjected to mutational analysis in order to (1) generate a collection of chromosome breakpoints that would allow a correlation between the genetic, cytological and molecular maps of the region and (2) define the number and gross organization of complementation groups within this interval. Eighteen complementation groups were defined and mapped to
Science, 2010
Our understanding of postcopulatory sexual selection has been constrained by an inability to disc... more Our understanding of postcopulatory sexual selection has been constrained by an inability to discriminate competing sperm of different males, coupled with challenges of directly observing live sperm inside the female reproductive tract. Real-time and spatiotemporal analyses of sperm movement, storage, and use within female Drosophila melanogaster inseminated by two transgenic males with, respectively, green and red sperm heads allowed us to unambiguously discriminate among hypothesized mechanisms underlying sperm precedence, including physical displacement and incapacitation of "resident" sperm by second males, female ejection of sperm, and biased use of competing sperm for fertilization. We find that competitive male fertilization success derives from a multivariate process involving ejaculate-female and ejaculate-ejaculate interactions, as well as complex sperm behavior in vivo.
MGG Molecular & General Genetics, 1995
Sex determination in Drosophila melanogaster is initiated in the early embryo by a signal provide... more Sex determination in Drosophila melanogaster is initiated in the early embryo by a signal provided by three types of genes: (1) X-linked numerator elements [e.g., sisterless-a (sis-a) and sisterless-b (sis-b)], (2) autosomally linked denominator elements [e.g., deadpan (dpn)], and (3) maternal factors [e.g., daughterless (da)]. This signal acts to stimulate transcription from an embryo-specific promoter of the master regulatory gene Sex-lethal (Sxl) in embryos that have two X chromosomes (females), while it fails to activate Sxl in those with only one X (males). It has been previously proposed that competitive dimerizations among the components of this signal might provide the molecular basis for this sex specificity. Here, we use the yeast two-hybrid system to demonstrate specific protein-protein interactions among the above-mentioned factors, and to delimit their interacting domains. These results support and extend the model of the molecular basis of the X/A ratio signal.
Molecular and General Genetics MGG, 1998
The proteasome plays essential roles in a variety of cellular processes, including degradation of... more The proteasome plays essential roles in a variety of cellular processes, including degradation of the bulk of cellular proteins, degradation of short-lived proteins such as cell cycle regulators, generation of antigenic peptides, and mediating programmed cell death. One of the best characterized subunits of the 26S proteasome is encoded by the yeast gene SUG1. We report here the cloning and characterization of the Drosophila homolog of this gene, Pros45. At the protein level, Pros45 is highly conserved with respect to its homologs in a variety of taxa: it shows 74% identity to yeast Sug1; 86% to mouse m56/mSug1/FZA-B; 87% to human Trip1; and 97% to moth 18-56. Using a genomic clone as a probe for in situ hyridization to polytene chromesomes, we demonstrated that Pros45 maps to 19F, near the base of the X chromosome. Use of a pros45 cDNA clone as a probe revealed a second site of hybridization at 99CD. Pros45 mRNA is found in the unfertilized egg and in all cells of the early embryo. By the end of embryogenesis, Pros45 is expressed predominantly in the central nervous system. Targeted expression of Pros45 in a variety of different cells using the Gal4 UAS P-element system failed to generate an overt phenotype. This study provides the foundation for further examination of the role of the 26S proteasome in homeostasis and development in Drosophila.
Heredity, 2009
The proteasome is a large, multisubunit complex that acts as the cell's 'protein-... more The proteasome is a large, multisubunit complex that acts as the cell's 'protein-degrading machine' in the ubiquitin-mediated proteolytic pathway for regulated protein turnover. Although proteasomes are usually thought of as being homogeneous structures, recent studies have revealed their more dynamic and heterogeneous nature. For example, in a number of plant and animal species, multiple isoforms of several proteasome subunits, encoded by paralogous genes, have been discovered, and in some cases, these alternative isoforms have been shown to be functionally distinct from their conventional counterparts. A particularly striking example of this phenomenon is seen in Drosophila melanogaster, where 12 of the 33 subunits that make up the 26S proteasome holoenzyme are represented in the genome by multiple paralogous genes. Remarkably, in every case, the 'extra' genes are expressed in a testis-specific manner. Here, we describe the extent and nature of these testis-specific gene duplications and discuss their functional significance, and speculate on why this situation might have evolved.
Gene, 1998
Proteasomes are large multisubunit particles that act as the proteolytic machinery for the ubiqui... more Proteasomes are large multisubunit particles that act as the proteolytic machinery for the ubiquitin-dependent proteolytic pathway. The core of this complex, the 20S proteasome, is made up of seven a-type and seven b-type subunits, arranged in an (a1-a7)( b1-b7)(b1-b7) (a1-a7) configuration. Previous work had shown that there exist alternative isoforms of the Drosophila melanogaster a4-type subunit, encoded by two distinct genes, a4t1_dm and a4t2_dm, and that these are expressed exclusively in the germline of the testes. We sought to investigate the evolutionary conservation of this phenomenon by screening for orthologs of the a4-type gene family in the distantly related Drosophila species, D. virilis. We isolated the D. virilis orthologs of the somatically expressed gene, a4_dm, and the testes-specific gene, a4t2_dm. We failed to find an ortholog of the other testes-specific gene, a4t1_dm. The a4_dv gene maps to the X chromosome at 12A-C, its product shares 90% amino acid identity with a4_dm, and it is expressed at high levels in both males and females. The other gene, a4t_dv, encodes a protein most similar to the testesspecific a4t2_dm proteasome subunit (59% a.a. identity), and it maps to position 27 on chomosome 2. The expression of the a4t_dv gene is testes-specific, like that of a4t2_dm. The existence of testes-specific a4-type subunits in two widely diverged subgenera of Drosophila suggests that these subunit isoforms have important functional roles in spermatogenesis.
Gene, 1998
The steady-state level of histone acetylation in eukaryotes is established and maintained by mult... more The steady-state level of histone acetylation in eukaryotes is established and maintained by multiple histone acetyltransferases (HATs) and histone deacetylases (HDACs) and affects both the structure and the function of chromatin. Histone deacetylases play a key role in the regulation of transcription, and form a highly conserved protein family in many eukaryotic species. Here we describe the cloning, sequencing and genetic mapping of two histone deacetylase genes in Drosophila melanogaster: dHDAC1 is essentially identical to the previously cloned D. melanogaster d-Rpd3 gene and dHDAC3, a novel gene, is orthologous to the human and the chicken (Gallus gallus) HDAC3 genes. The predicted amino acid sequence (438 aa) of dHDAC3 shows 58.1% identity with dHDAC1/d-Rpd3, the only previously known member of the HDAC family in this organism. The map positions on polytene chromosomes for dHDAC1 and dHDAC3 were determined as 64C1-6 and 83A3-4 respectively. A search for other dHDAC3-like genes failed to find other potential paralogues in D. melanogaster, but identified significant homologies with bacterial and fungal genes encoding enzymes that metabolise acetyl groups, and with genes for other hydrolyases such as carboxypeptidase. In addition, histone deacetylase activity in D. melanogaster nuclear extracts can be inhibited by high concentrations of zinc and activated by low concentrations, which is identical to the properties of bovine carboxypeptidase A. On the basis of sequence and functional similarities, we suggest that histone deacetylases are metal-substituted enzymes.
Genetics, 1996
Using the previously cloned proteasome {alpha}-type subunit gene Pros28. 1, we screened a Drosoph... more Using the previously cloned proteasome {alpha}-type subunit gene Pros28. 1, we screened a Drosophila melanogaster genomic library using reduced stringency conditions to identify closely related genes. Two new genes, Pros28. 1A (map position 92F) and Pros28. 1B ( ...
Behavioral Ecology, 2011
In contrast to early predictions, it is now widely accepted that males incur substantive costs fr... more In contrast to early predictions, it is now widely accepted that males incur substantive costs from ejaculate production. Hence, males are predicted to allocate their reproductive investments, including ejaculate size, relative to the risk of sperm competition and to female quality. The study of sperm allocation, however, has been technically challenging with nonvirgin females because sperm from different males must be discriminated within the female reproductive tract. To date, such investigations have thus largely been restricted to species that transfer sperm in spermatophores or for which females can be fitted with a harness to capture the incoming ejaculate. In this study, we examined sperm allocation using male Drosophila melanogaster that express a fluorescently labeled protein in sperm heads, allowing us to quantify sperm numbers from different males within the female reproductive tract. We found that male D. melanogaster deliver significantly more sperm to mated, large or young females compared with virgins, small or old females, respectively, whereas copulation duration was only significantly longer with large than with small females. These results provide further evidence for costly ejaculate production and consequent prudent allocation of sperm.
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1995
Multiple mitochondrial ATPase inhibitor genes have been identified in the rat genome. The sequenc... more Multiple mitochondrial ATPase inhibitor genes have been identified in the rat genome. The sequences of two genomic clones indicate that one encodes the functional gene, and the other is a processed pseudogene. The ATPase inhibitor gene isolated is about 1.5 kb long and the coding region contains three exons and two introns. The presence of multiple pseudogenes in the rat is suggested by this study and this is unique since in the bovine genome only a single gene has been found, which is also confirmed here. The presence of multiple inhibitor transcripts in the rat suggests that the functional gene might have multiple transcriptional start sites.
Annual Review of Genetics, 1983
... All rights reserved SEX DETERMINATION AND DOSAGE COMPENSATION IN DROSOPHILA MELANOGASTER Bruc... more ... All rights reserved SEX DETERMINATION AND DOSAGE COMPENSATION IN DROSOPHILA MELANOGASTER Bruce S. Baker and John M. Belote Department of Biology, University of California at San Diego, La Jolla, California 92093 CONTENTS INTRODUCTION..... ...
Journal of Insect Physiology, 2014
Mating between relatives usually decreases genetic quality of progeny as deleterious recessive al... more Mating between relatives usually decreases genetic quality of progeny as deleterious recessive alleles are expressed in inbred individuals. Inbreeding degrades sperm traits but its effects on sperm storage and fate within females are currently unknown. We quantified the relationship between the degrees of inbreeding relevant to natural populations (f=0, 0.25 and 0.50) and the number of sperm inseminated and stored, sperm swimming speed, long-term sperm viability while in storage, pattern of sperm precedence, mating latency, and offspring viability of female Drosophila melanogaster. The use of transgenic flies that have either red or green fluorescent sperm heads allowed us to distinguish two ejaculates in the female reproductive tract and facilitated quantification of sperm storage and use traits. We found no inbreeding depression in either long- or short-term sperm storage ability. The most inbred females exhibited significantly longer mating latency, which could be explained by males preferring to mate with outbred females. On the other hand, as no evidence for cryptic male choice in the form of ejaculate tailoring of sperm number was found, the most inbred females might just be less eager to mate. We also found no evidence that the degree of maternal inbreeding influenced offspring viability. Comparison with a contemporaneous study of male inbreeding consequences for ejaculate quality suggests that inbreeding depression is more severe in males than in females in our study population.
Ecology and Evolution, 2013
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when sele... more Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer the mode of past selection on them. The use of transgenic populations of Drosophila melanogaster with red or green fluorescent-tagged sperm heads permitted in vivo discrimination of sperm from competing males and quantification of characteristics of ejaculate composition, performance, and fate. We found that male attractiveness (mating latency) and competitive fertilization success (P2) both show some inbreeding depression, suggesting they may have been under directional selection, whereas sperm length showed no inbreeding depression suggesting a history of stabilizing selection. However, despite having measured several sperm quality and quantity traits, our data did not allow us to discern the mechanism underlying the lowered competitive fertilization success of inbred (f = 0.50) males.
Nucleic Acids Research, 1998
PCAF and hGCN5 are distinct human genes that encode proteins related to the yeast histone acetylt... more PCAF and hGCN5 are distinct human genes that encode proteins related to the yeast histone acetyltransferase and transcriptional adapter GCN5. The PCAF protein shares extensive similarity with the 439 amino acids of yGCN5, but it has an ~350 amino acid N-terminal extension that interacts with the transcriptional co-acti- vator p300/CBP. Adenoviral protein E1a can disrupt PCAF-CBP interactions and prevent PCAF-dependent
The 73AD salivary chromosome region of Drosophila melanogaster was subjected to mutational analys... more The 73AD salivary chromosome region of Drosophila melanogaster was subjected to mutational analysis in order to (1) generate a collection of chromosome breakpoints that would allow a correlation between the genetic, cytological and molecular maps of the region and (2) define the number and gross organization of complementation groups within this interval. Eighteen complementation groups were defined and mapped to
Science, 2010
Our understanding of postcopulatory sexual selection has been constrained by an inability to disc... more Our understanding of postcopulatory sexual selection has been constrained by an inability to discriminate competing sperm of different males, coupled with challenges of directly observing live sperm inside the female reproductive tract. Real-time and spatiotemporal analyses of sperm movement, storage, and use within female Drosophila melanogaster inseminated by two transgenic males with, respectively, green and red sperm heads allowed us to unambiguously discriminate among hypothesized mechanisms underlying sperm precedence, including physical displacement and incapacitation of "resident" sperm by second males, female ejection of sperm, and biased use of competing sperm for fertilization. We find that competitive male fertilization success derives from a multivariate process involving ejaculate-female and ejaculate-ejaculate interactions, as well as complex sperm behavior in vivo.
MGG Molecular & General Genetics, 1995
Sex determination in Drosophila melanogaster is initiated in the early embryo by a signal provide... more Sex determination in Drosophila melanogaster is initiated in the early embryo by a signal provided by three types of genes: (1) X-linked numerator elements [e.g., sisterless-a (sis-a) and sisterless-b (sis-b)], (2) autosomally linked denominator elements [e.g., deadpan (dpn)], and (3) maternal factors [e.g., daughterless (da)]. This signal acts to stimulate transcription from an embryo-specific promoter of the master regulatory gene Sex-lethal (Sxl) in embryos that have two X chromosomes (females), while it fails to activate Sxl in those with only one X (males). It has been previously proposed that competitive dimerizations among the components of this signal might provide the molecular basis for this sex specificity. Here, we use the yeast two-hybrid system to demonstrate specific protein-protein interactions among the above-mentioned factors, and to delimit their interacting domains. These results support and extend the model of the molecular basis of the X/A ratio signal.
Molecular and General Genetics MGG, 1998
The proteasome plays essential roles in a variety of cellular processes, including degradation of... more The proteasome plays essential roles in a variety of cellular processes, including degradation of the bulk of cellular proteins, degradation of short-lived proteins such as cell cycle regulators, generation of antigenic peptides, and mediating programmed cell death. One of the best characterized subunits of the 26S proteasome is encoded by the yeast gene SUG1. We report here the cloning and characterization of the Drosophila homolog of this gene, Pros45. At the protein level, Pros45 is highly conserved with respect to its homologs in a variety of taxa: it shows 74% identity to yeast Sug1; 86% to mouse m56/mSug1/FZA-B; 87% to human Trip1; and 97% to moth 18-56. Using a genomic clone as a probe for in situ hyridization to polytene chromesomes, we demonstrated that Pros45 maps to 19F, near the base of the X chromosome. Use of a pros45 cDNA clone as a probe revealed a second site of hybridization at 99CD. Pros45 mRNA is found in the unfertilized egg and in all cells of the early embryo. By the end of embryogenesis, Pros45 is expressed predominantly in the central nervous system. Targeted expression of Pros45 in a variety of different cells using the Gal4 UAS P-element system failed to generate an overt phenotype. This study provides the foundation for further examination of the role of the 26S proteasome in homeostasis and development in Drosophila.
Heredity, 2009
The proteasome is a large, multisubunit complex that acts as the cell's 'protein-... more The proteasome is a large, multisubunit complex that acts as the cell's 'protein-degrading machine' in the ubiquitin-mediated proteolytic pathway for regulated protein turnover. Although proteasomes are usually thought of as being homogeneous structures, recent studies have revealed their more dynamic and heterogeneous nature. For example, in a number of plant and animal species, multiple isoforms of several proteasome subunits, encoded by paralogous genes, have been discovered, and in some cases, these alternative isoforms have been shown to be functionally distinct from their conventional counterparts. A particularly striking example of this phenomenon is seen in Drosophila melanogaster, where 12 of the 33 subunits that make up the 26S proteasome holoenzyme are represented in the genome by multiple paralogous genes. Remarkably, in every case, the 'extra' genes are expressed in a testis-specific manner. Here, we describe the extent and nature of these testis-specific gene duplications and discuss their functional significance, and speculate on why this situation might have evolved.
Gene, 1998
Proteasomes are large multisubunit particles that act as the proteolytic machinery for the ubiqui... more Proteasomes are large multisubunit particles that act as the proteolytic machinery for the ubiquitin-dependent proteolytic pathway. The core of this complex, the 20S proteasome, is made up of seven a-type and seven b-type subunits, arranged in an (a1-a7)( b1-b7)(b1-b7) (a1-a7) configuration. Previous work had shown that there exist alternative isoforms of the Drosophila melanogaster a4-type subunit, encoded by two distinct genes, a4t1_dm and a4t2_dm, and that these are expressed exclusively in the germline of the testes. We sought to investigate the evolutionary conservation of this phenomenon by screening for orthologs of the a4-type gene family in the distantly related Drosophila species, D. virilis. We isolated the D. virilis orthologs of the somatically expressed gene, a4_dm, and the testes-specific gene, a4t2_dm. We failed to find an ortholog of the other testes-specific gene, a4t1_dm. The a4_dv gene maps to the X chromosome at 12A-C, its product shares 90% amino acid identity with a4_dm, and it is expressed at high levels in both males and females. The other gene, a4t_dv, encodes a protein most similar to the testesspecific a4t2_dm proteasome subunit (59% a.a. identity), and it maps to position 27 on chomosome 2. The expression of the a4t_dv gene is testes-specific, like that of a4t2_dm. The existence of testes-specific a4-type subunits in two widely diverged subgenera of Drosophila suggests that these subunit isoforms have important functional roles in spermatogenesis.
Gene, 1998
The steady-state level of histone acetylation in eukaryotes is established and maintained by mult... more The steady-state level of histone acetylation in eukaryotes is established and maintained by multiple histone acetyltransferases (HATs) and histone deacetylases (HDACs) and affects both the structure and the function of chromatin. Histone deacetylases play a key role in the regulation of transcription, and form a highly conserved protein family in many eukaryotic species. Here we describe the cloning, sequencing and genetic mapping of two histone deacetylase genes in Drosophila melanogaster: dHDAC1 is essentially identical to the previously cloned D. melanogaster d-Rpd3 gene and dHDAC3, a novel gene, is orthologous to the human and the chicken (Gallus gallus) HDAC3 genes. The predicted amino acid sequence (438 aa) of dHDAC3 shows 58.1% identity with dHDAC1/d-Rpd3, the only previously known member of the HDAC family in this organism. The map positions on polytene chromosomes for dHDAC1 and dHDAC3 were determined as 64C1-6 and 83A3-4 respectively. A search for other dHDAC3-like genes failed to find other potential paralogues in D. melanogaster, but identified significant homologies with bacterial and fungal genes encoding enzymes that metabolise acetyl groups, and with genes for other hydrolyases such as carboxypeptidase. In addition, histone deacetylase activity in D. melanogaster nuclear extracts can be inhibited by high concentrations of zinc and activated by low concentrations, which is identical to the properties of bovine carboxypeptidase A. On the basis of sequence and functional similarities, we suggest that histone deacetylases are metal-substituted enzymes.
Genetics, 1996
Using the previously cloned proteasome {alpha}-type subunit gene Pros28. 1, we screened a Drosoph... more Using the previously cloned proteasome {alpha}-type subunit gene Pros28. 1, we screened a Drosophila melanogaster genomic library using reduced stringency conditions to identify closely related genes. Two new genes, Pros28. 1A (map position 92F) and Pros28. 1B ( ...
Behavioral Ecology, 2011
In contrast to early predictions, it is now widely accepted that males incur substantive costs fr... more In contrast to early predictions, it is now widely accepted that males incur substantive costs from ejaculate production. Hence, males are predicted to allocate their reproductive investments, including ejaculate size, relative to the risk of sperm competition and to female quality. The study of sperm allocation, however, has been technically challenging with nonvirgin females because sperm from different males must be discriminated within the female reproductive tract. To date, such investigations have thus largely been restricted to species that transfer sperm in spermatophores or for which females can be fitted with a harness to capture the incoming ejaculate. In this study, we examined sperm allocation using male Drosophila melanogaster that express a fluorescently labeled protein in sperm heads, allowing us to quantify sperm numbers from different males within the female reproductive tract. We found that male D. melanogaster deliver significantly more sperm to mated, large or young females compared with virgins, small or old females, respectively, whereas copulation duration was only significantly longer with large than with small females. These results provide further evidence for costly ejaculate production and consequent prudent allocation of sperm.
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1995
Multiple mitochondrial ATPase inhibitor genes have been identified in the rat genome. The sequenc... more Multiple mitochondrial ATPase inhibitor genes have been identified in the rat genome. The sequences of two genomic clones indicate that one encodes the functional gene, and the other is a processed pseudogene. The ATPase inhibitor gene isolated is about 1.5 kb long and the coding region contains three exons and two introns. The presence of multiple pseudogenes in the rat is suggested by this study and this is unique since in the bovine genome only a single gene has been found, which is also confirmed here. The presence of multiple inhibitor transcripts in the rat suggests that the functional gene might have multiple transcriptional start sites.
Annual Review of Genetics, 1983
... All rights reserved SEX DETERMINATION AND DOSAGE COMPENSATION IN DROSOPHILA MELANOGASTER Bruc... more ... All rights reserved SEX DETERMINATION AND DOSAGE COMPENSATION IN DROSOPHILA MELANOGASTER Bruce S. Baker and John M. Belote Department of Biology, University of California at San Diego, La Jolla, California 92093 CONTENTS INTRODUCTION..... ...
Journal of Insect Physiology, 2014
Mating between relatives usually decreases genetic quality of progeny as deleterious recessive al... more Mating between relatives usually decreases genetic quality of progeny as deleterious recessive alleles are expressed in inbred individuals. Inbreeding degrades sperm traits but its effects on sperm storage and fate within females are currently unknown. We quantified the relationship between the degrees of inbreeding relevant to natural populations (f=0, 0.25 and 0.50) and the number of sperm inseminated and stored, sperm swimming speed, long-term sperm viability while in storage, pattern of sperm precedence, mating latency, and offspring viability of female Drosophila melanogaster. The use of transgenic flies that have either red or green fluorescent sperm heads allowed us to distinguish two ejaculates in the female reproductive tract and facilitated quantification of sperm storage and use traits. We found no inbreeding depression in either long- or short-term sperm storage ability. The most inbred females exhibited significantly longer mating latency, which could be explained by males preferring to mate with outbred females. On the other hand, as no evidence for cryptic male choice in the form of ejaculate tailoring of sperm number was found, the most inbred females might just be less eager to mate. We also found no evidence that the degree of maternal inbreeding influenced offspring viability. Comparison with a contemporaneous study of male inbreeding consequences for ejaculate quality suggests that inbreeding depression is more severe in males than in females in our study population.