A constituent part of a marker for marking discrete entities including a support structure, at least one first oligonucleotide connected to the support structure, at least a second oligonucleotide at least partially complementary to a part of the first oligonucleotide, and at least one label connected to the second oligonucleotide.

A constituent part of a marker for marking discrete entities including a support structure, at least one first oligonucleotide connected to the support structure, at least a second oligonucleotide at least partially complementary to a part of the first oligonucleotide, and at least one label connected to the second oligonucleotide.

Provided herein, among other things, is a method for synthesizing spatially addressed nucleic acid barcodes in or on a cellular sample in situ. In some embodiments, the method may comprise: obtaining a cellular sample comprising nucleic acid molecules that are protected by a reversible terminator, deprotecting the nucleic acid molecules in a set of areas of the sample by selectively applying an external stimulus to the set of areas to produce deprotected nucleic acid molecules in the areas, applying a reversible terminator nucleotide to the cellular sample, resulting in addition of a reversible terminator onto the deprotected nucleic acid molecules, optionally removing any unreacted reversible terminator nucleotide from the sample, and repeating the steps one or more times.

Provided herein, among other things, is a method for synthesizing spatially addressed nucleic acid barcodes in or on a cellular sample in situ. In some embodiments, the method may comprise: obtaining a cellular sample comprising nucleic acid molecules that are protected by a reversible terminator, deprotecting the nucleic acid molecules in a set of areas of the sample by selectively applying an external stimulus to the set of areas to produce deprotected nucleic acid molecules in the areas, applying a reversible terminator nucleotide to the cellular sample, resulting in addition of a reversible terminator onto the deprotected nucleic acid molecules, optionally removing any unreacted reversible terminator nucleotide from the sample, and repeating the steps one or more times.

Provided herein, among other things, is a method for synthesizing spatially addressed nucleic acid barcodes in or on a cellular sample in situ. In some embodiments, the method may comprise: obtaining a cellular sample comprising nucleic acid molecules that are protected by a reversible terminator, deprotecting the nucleic acid molecules in a set of areas of the sample by selectively applying an external stimulus to the set of areas to produce deprotected nucleic acid molecules in the areas, applying a reversible terminator nucleotide to the cellular sample, resulting in addition of a reversible terminator onto the deprotected nucleic acid molecules, optionally removing any unreacted reversible terminator nucleotide from the sample, and repeating the steps one or more times.

Methods and compositions for determining the proximity of two barcoding oligonucleotides (e.g., in a single partition or adjacent on a tissue section) using a determination of the presence of a 9 bp sequence resulting from tagmentation in different nucleic acid fragments linked to different barcoding oligonucleotides is provided.

Disclosed herein include methods and compositions for culture medias for in vitro culture of synthetic embryos from mammalian pluripotent stem cells and extra-embryonic stem cells. The methods and compositions described herein can generate synthetic embryos at different developmental stage reaching early organogenesis and beyond. Disclosed herein also include an embryo culturing system and methods of using same.

Disclosed herein include methods and compositions for culture medias for in vitro culture of synthetic embryos from mammalian pluripotent stem cells and extra-embryonic stem cells. The methods and compositions described herein can generate synthetic embryos at different developmental stage reaching early organogenesis and beyond. Disclosed herein also include an embryo culturing system and methods of using same.

The invention relates to a method for the detection of the occurrence of initiation of replication events in genomic DNA in a eukaryotic cell, involving contacting said eukaryotic cell comprising said genomic DNA with a first nucleotide probe, under conditions enabling in situ hybridization of said first nucleotide probe with a target region in the DNA genome, wherein said target region comprises a nucleic acid sequence which has no identified corresponding annealing RNA in a metabolically active cell and therefore remains RNA-free during transcription and replication of said DNA genome and detecting said first nucleotide probe hybridized to said DNA. Further detection of at least one RNA molecule can be achieved. The invention also relates to a nucleic acid molecule suitable for use as a probe, hybridizing with a target region in a eukaryotic genomic DNA, and comprising a nucleic acid sequence which has no identified corresponding annealing RNA in the metabolically active cell containing said eukaryotic genomic DNA and therefore remains RNA-free during transcription and replication of said DNA genome. The invention also encompasses kit(s) for carrying out in situ hybridization and use of the method(s), nucleic acid molecule(s) or kit(s) of the invention in the detection of mitochondrial disease(s), neoplasic diseases(s) or cancer(s), or in the testing of the cytotoxicity of organic or chemical compounds, especially drugs, on eukaryotic cells.

The invention relates to a method for the detection of the occurrence of initiation of replication events in genomic DNA in a eukaryotic cell, involving contacting said eukaryotic cell comprising said genomic DNA with a first nucleotide probe, under conditions enabling in situ hybridization of said first nucleotide probe with a target region in the DNA genome, wherein said target region comprises a nucleic acid sequence which has no identified corresponding annealing RNA in a metabolically active cell and therefore remains RNA-free during transcription and replication of said DNA genome and detecting said first nucleotide probe hybridized to said DNA. Further detection of at least one RNA molecule can be achieved. The invention also relates to a nucleic acid molecule suitable for use as a probe, hybridizing with a target region in a eukaryotic genomic DNA, and comprising a nucleic acid sequence which has no identified corresponding annealing RNA in the metabolically active cell containing said eukaryotic genomic DNA and therefore remains RNA-free during transcription and replication of said DNA genome. The invention also encompasses kit(s) for carrying out in situ hybridization and use of the method(s), nucleic acid molecule(s) or kit(s) of the invention in the detection of mitochondrial disease(s), neoplasic diseases(s) or cancer(s), or in the testing of the cytotoxicity of organic or chemical compounds, especially drugs, on eukaryotic cells.