Female X-STR Reference Standard for Cell ID

Product Overview

The Female X-STR Reference Standard for Cell ID is a specialized reference material designed for validating X-chromosome short tandem repeat (X-STR) profiling workflows in human cell line authentication and gender-specific identity testing. This high-quality genomic DNA standard derives from a genetically characterized female donor, providing verified allelic profiles across 16 X-chromosome STR loci critical for complex relationship testing and cell line sex verification. With comprehensive validation against international reference standards, it serves as an essential tool for forensic laboratories, cell banks, and biobanks requiring reliable gender-specific controls in identity verification protocols .

Product Features

Comprehensive X-STR Locus Coverage

Includes validated alleles for 16 X-chromosome STR loci, including the International Society for Forensic Genetics (ISFG) recommended markers: DXS6807, DXS8378, DXS10135, DXS10148, DXS10164, DXS10162, and amelogenin (AMEL-X). Each locus is quantified to ensure balanced peak heights and accurate allele sizing across capillary electrophoresis platforms .

Gender-Specific Genotype Verification

Contains a confirmed female genotype with homozygous X-chromosome markers and complete absence of Y-chromosome sequences (AMEL-Y negative). This provides a definitive reference for validating gender determination algorithms in identity testing software .

High-Quality DNA Matrix

Purified to >99% genomic integrity with A260/A280 ratio of 1.8-2.0, ensuring minimal PCR inhibition. The DNA is supplied at 50 ng/μL in TE buffer (pH 8.0) with preservatives to maintain stability during storage and handling .

Usage

STR Protocol Validation

Use to validate X-STR profiling protocols by:

• Verifying allele call accuracy across all 16 loci

• Optimizing PCR cycling conditions for X-chromosome markers

• Establishing intra-run and inter-run precision metrics

• Calibrating capillary electrophoresis fragment analysis settings

Cell Line Authentication

Include as a gender-specific control in cell line authentication panels to:

• Confirm female origin of unknown cell lines

• Detect cross-contamination with male cell lines

• Validate STR database matching algorithms

• Ensure compliance with ATCC authentication standards

Preparation Instructions

Dilute standard to 1 ng/μL working concentration using molecular biology-grade water. Use 1 μL per PCR reaction (1 ng input) for optimal amplification. Prepare serial dilutions (0.1-10 ng) to establish assay sensitivity limits .

FAQ

Why are X-STR markers important for cell line authentication?

X-STR markers provide higher discrimination power than autosomal STRs for gender verification and can detect low-level cross-contamination between male and female cell lines, a common issue in cell culture facilities .

How is the female genotype verified?

The genotype is confirmed through multiple orthogonal methods including karyotyping, fluorescence in situ hybridization (FISH) for sex chromosomes, and replicate STR profiling across multiple platforms (ABI 3500 and SeqStudio) .

Can this standard be used with commercial STR kits?

Yes, it is validated for use with all major commercial X-STR kits including Promega PowerPlex® X and Thermo Fisher Applied Biosystems GlobalFiler™ Express, with kit-specific allele calls provided in the certificate of analysis .

What is the stability of the standard after reconstitution?

When stored at 4°C, reconstituted standard remains stable for up to 60 days. For long-term storage, aliquot and freeze at -20°C for up to 12 months, avoiding more than 5 freeze-thaw cycles .