High-frequency germ-line transmission of plasmid DNA sequences injected into fertilized zebrafish eggs.

Gene conversion is the nonreciprocal transfer of genetic information between two related genes or DNA sequences. It can influence the evolution of gene families, having the capacity to generate both diversity and homogeneity. The potential evolutionary significance of this process is directly related to its frequency in the germ line. While measurement of meiotic inter- and intrachromosomal gene conversion frequency is routine in fungal systems, it has hitherto been impractical in mammals. We have designed a system for identifying and quantitating germ line gene conversion in mice by analyzing transgenic male gametes for a contrived recombination event. Spermatids which undergo the designed intrachromosomal gene conversion produce functional beta-galactosidase (encoded by the lacZ gene), which is visualized by histochemical staining. We observed a high incidence of lacZ-positive spermatids (approximately 2%), which were produced by a combination of meiotic and mitotic conversion events. These results demonstrate that gene conversion in mice is an active recombinational process leading to nonparental gametic haplotypes. This high frequency of intrachromosomal gene conversion seems incompatible with the evolutionary divergence of newly duplicated genes. Hence, a process may exist to uncouple gene pairs from frequent conversion-mediated homogenization.

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Distribution, expression and germ line transmission of exogenous DNA sequences following microinjection into Xenopus laevis eggs

Development ◽

10.1242/dev.99.1.15 ◽

1987 ◽

Vol 99 (1) ◽

pp. 15-23

Author(s):

L.D. Etkin ◽

B. Pearman

Keyword(s):

Xenopus Laevis ◽

Dna Sequences ◽

Copy Number ◽

Germ Line ◽

Gene Promoter ◽

Early Gene ◽

Mosaic Pattern ◽

Exogenous Dna ◽

Gene Coding ◽

Germ Line Transmission

We analysed the fate, expression and germ line transmission of exogenous DNA which was microinjected into fertilized eggs of Xenopus laevis. DNA was injected into fertilized eggs within 1 h following fertilization. The injected DNA was dispersed around the site of injection and became localized to cleavage nuclei by stage 6. Injected DNA persisted in the tissues of 6- to 8-month-old frogs and exhibited a mosaic pattern of distribution with regard to the presence or absence and copy number between different tissues. We detected the exogenous DNA sequences in 60% of injected frogs. Restriction digestion analysis of this DNA suggested that it is not rearranged and was organized as head-to-tail multimers. The copy number varied from 2 to 30 copies/cell in various tissues of the same frog. Plasmid pSV2CAT which contains the prokaryotic gene coding for chloramphenicol acetyl transferase (CAT) enzyme linked to the SV40 early gene promoter was expressed in 50% of the animals containing the gene. The pattern of expression, however, varied between different animals and could not be correlated with copy number. We also showed that the exogenous DNA sequences were transmitted through the male germ line and that each offspring contained the gene integrated into a different region of the genome.

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Production of Transgenic Quails with High Frequency of Germ-Line Transmission Using VSV-G Pseudotyped Retroviral Vector

Biochemical and Biophysical Research Communications ◽

10.1006/bbrc.2001.5422 ◽

2001 ◽

Vol 286 (3) ◽

pp. 456-463 ◽

Cited By ~ 71

Author(s):

Shinji Mizuarai ◽

Ken-ichiro Ono ◽

Kazuhisa Yamaguchi ◽

Ken-ichi Nishijima ◽

Masamichi Kamihira ◽

...

Keyword(s):

High Frequency ◽

Germ Line ◽

Retroviral Vector ◽

Germ Line Transmission

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High-frequency germ line gene conversion in transgenic mice.

Molecular and Cellular Biology ◽

10.1128/mcb.12.6.2545 ◽

1992 ◽

Vol 12 (6) ◽

pp. 2545-2552 ◽

Cited By ~ 39

Author(s):

J R Murti ◽

M Bumbulis ◽

J C Schimenti

Keyword(s):

Gene Conversion ◽

Dna Sequences ◽

High Frequency ◽

Germ Line ◽

Gene Families ◽

Histochemical Staining ◽

Evolutionary Significance ◽

Evolutionary Divergence ◽

Lacz Gene ◽

Male Gametes

Gene conversion is the nonreciprocal transfer of genetic information between two related genes or DNA sequences. It can influence the evolution of gene families, having the capacity to generate both diversity and homogeneity. The potential evolutionary significance of this process is directly related to its frequency in the germ line. While measurement of meiotic inter- and intrachromosomal gene conversion frequency is routine in fungal systems, it has hitherto been impractical in mammals. We have designed a system for identifying and quantitating germ line gene conversion in mice by analyzing transgenic male gametes for a contrived recombination event. Spermatids which undergo the designed intrachromosomal gene conversion produce functional beta-galactosidase (encoded by the lacZ gene), which is visualized by histochemical staining. We observed a high incidence of lacZ-positive spermatids (approximately 2%), which were produced by a combination of meiotic and mitotic conversion events. These results demonstrate that gene conversion in mice is an active recombinational process leading to nonparental gametic haplotypes. This high frequency of intrachromosomal gene conversion seems incompatible with the evolutionary divergence of newly duplicated genes. Hence, a process may exist to uncouple gene pairs from frequent conversion-mediated homogenization.

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Germ-line transmission of trisomy 21: Data from 80 families suggest an implication of grandmaternal age and a high frequency of female-specific trisomy rescue

Molecular Cytogenetics ◽

10.1186/1755-8166-3-7 ◽

2010 ◽

Vol 3 (1) ◽

pp. 7 ◽

Cited By ~ 13

Author(s):

Natalia V Kovaleva

Keyword(s):

High Frequency ◽

Trisomy 21 ◽

Germ Line ◽

Female Specific ◽

Germ Line Transmission ◽

Trisomy Rescue

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Parasites in Antarctic krill guts inferred from DNA sequences

Antarctic Science ◽

10.1017/s0954102018000469 ◽

2019 ◽

Vol 31 (1) ◽

pp. 16-22 ◽

Cited By ~ 2

Author(s):

Alison C. Cleary ◽

Maria C. Casas ◽

Edward G. Durbin ◽

Jaime Gómez-Gutiérrez

Keyword(s):

Dna Sequences ◽

High Frequency ◽

Dna Analysis ◽

Antarctic Krill ◽

Euphausia Superba ◽

Gut Contents ◽

The West ◽

West Antarctic ◽

Wide Range

AbstractThe keystone role of Antarctic krill,Euphausia superbaDana, in Southern Ocean ecosystems, means it is essential to understand the factors controlling their abundance and secondary production. One such factor that remains poorly known is the role of parasites. A recent study of krill diet using DNA analysis of gut contents provided a snapshot of the parasites present within 170E. superbaguts in a small area along the West Antarctic Peninsula. These parasites includedMetschnikowiaspp. fungi,Haptoglossasp. peronosporomycetes,LankesteriaandParalecudinaspp. apicomplexa,Stegophorussp. nematodes, andPseudocolliniaspp. ciliates. Of these parasites,Metschnikowiaspp. fungi andPseudocolliniaspp. ciliates had previously been observed inE. superba, as had other genera of apicomplexans, though notLankesteriaandParalecudina.In contrast, nematodes had previously only been observed in eggs ofE. superba, and there are no literature reports of peronosporomycetes in euphausiids.Pseudocolliniaspp., parasitoids which obligately kill their host, were the most frequently observed infection, with a prevalence of 12%. The wide range of observed parasites and the relatively high frequency of infections suggest parasites may play a more important role than previously acknowledged inE. superbaecology and population dynamics.

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Highly repetitive DNA sequences that are restricted to the germ line in the hagfish Eptatretus cirrhatus : a mosaic of eliminated elements

Chromosoma ◽

10.1007/s004120050278 ◽

1998 ◽

Vol 107 (1) ◽

pp. 17-32 ◽

Cited By ~ 14

Author(s):

Yuji Goto ◽

Souichirou Kubota ◽

Sei-ichi Kohno

Keyword(s):

Repetitive Dna ◽

Dna Sequences ◽

Germ Line ◽

Repetitive Dna Sequences ◽

Highly Repetitive Dna

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Insertion and excision of Caenorhabditis elegans transposable element Tc1

Molecular and Cellular Biology ◽

10.1128/mcb.8.2.737-746.1988 ◽

1988 ◽

Vol 8 (2) ◽

pp. 737-746

Author(s):

D Eide ◽

P Anderson

Keyword(s):

Amino Acid ◽

Caenorhabditis Elegans ◽

Transposable Element ◽

Dna Sequences ◽

Germ Line ◽

Consensus Sequence ◽

Somatic Cells ◽

Chain Gene ◽

Imprecise Excision ◽

Insertion Sites

The transposable element Tc1 is responsible for most spontaneous mutations that occur in Caenorhabditis elegans variety Bergerac. We investigated the genetic and molecular properties of Tc1 transposition and excision. We show that Tc1 insertion into the unc-54 myosin heavy-chain gene was strongly site specific. The DNA sequences of independent Tc1 insertion sites were similar to each other, and we present a consensus sequence for Tc1 insertion that describes these similarities. We show that Tc1 excision was usually imprecise. Tc1 excision was imprecise in both germ line and somatic cells. Imprecise excision generated novel unc-54 alleles that had amino acid substitutions, amino acid insertions, and, in certain cases, probably altered mRNA splicing. The DNA sequences remaining after Tc1 somatic excision were the same as those remaining after germ line excision, but the frequency of somatic excision was at least 1,000-fold higher than that of germ line excision. The genetic properties of Tc1 excision, combined with the DNA sequences of the resulting unc-54 alleles, demonstrated that excision was dependent on Tc1 transposition functions in both germ line and somatic cells. Somatic excision was not regulated in the same strain-specific manner as germ-line excision was. In a genetic background where Tc1 transposition and excision in the germ line was not detectable, Tc1 excision in the soma still occurred at high frequency.

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Germ line transmission of an inactive N-myc allele generated by homologous recombination in mouse embryonic stem cells

Molecular and Cellular Biology ◽

10.1128/mcb.10.12.6755-6758.1990 ◽

1990 ◽

Vol 10 (12) ◽

pp. 6755-6758

Author(s):

B R Stanton ◽

S W Reid ◽

L F Parada

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Homologous Recombination ◽

Embryonic Development ◽

Cell Lines ◽

Germ Line ◽

Es Cells ◽

Embryonic Stem ◽

Es Cell ◽

Germ Line Transmission

We have disrupted one allele of the N-myc locus in mouse embryonic stem (ES) cells by using homologous recombination techniques and have obtained germ line transmission of null N-myc ES cell lines with transmission of the null N-myc allele to the offspring. The creation of mice with a deficient N-myc allele will allow the generation of offspring bearing null N-myc alleles in both chromosomes and permit study of the role that this proto-oncogene plays in embryonic development.

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