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Avian Genetics

Overview: This section covers the scientific foundations of avian genetics — chromosome organization, the ZW sex-determination system, the CHD gene marker, and how DNA variation between species is measured and applied in diagnostic testing.

Core Articles

Avian Genetics Explained

How DNA determines bird characteristics: chromosome systems, ZW sex determination, and genetic variation between species.

[Read →](avian-genetics-explained.md)

Bird Sex Chromosomes: ZZ and ZW

The avian sex chromosome system in depth — why females are heterogametic and how this shapes inheritance.

[Read →](bird-sex-chromosomes-zz-zw.md)

CHD Gene in Sex Determination

The molecular mechanism of DNA sex testing: CHD-Z/CHD-W intron polymorphism, PCR workflow, and quality control.

[Read →](chd-gene-sex-determination.md)

Key Concepts

Concept Summary
ZW system Females are ZW (heterogametic); males are ZZ — opposite of mammals
CHD gene Chromo-Helicase-DNA binding gene; intron length differs between Z and W copies
DNA sexing PCR-based test: one band = male, two bands = female
Bird karyotype 2n = 78–80 with many microchromosomes
Genome size ~1.0–1.5 Gb — one-third of mammalian genomes