Chromosomes

Chromosomes are the carriers of genetic information in the cell nucleus and determine which traits your dog inherits from its parents – from coat colour to possible health problems.

How many chromosomes does my dog have?

Every dog has 78 chromosomes, arranged in 39 pairs. 38 pairs determine physical characteristics and functions; one pair determines sex. Bitches carry two X chromosomes (XX), dogs one X and one Y chromosome (XY).

The number of chromosomes is identical in all dog breeds – whether Chihuahua or Great Dane. For comparison: humans have only 46 chromosomes.

Why are chromosomes relevant for dog owners?

The genes on the chromosomes determine whether your dog remains healthy or develops a hereditary disease. Every puppy inherits one set of chromosomes from its mother and one from its father – and thus their genetic predispositions.

An example: The gene for hip dysplasia is located on several chromosomes. If a parent has an unfavourable gene variant, the puppy can inherit it. Reputable breeders therefore have their breeding dogs tested for hereditary diseases.

Which hereditary diseases are passed on via chromosomes?

Many breed-typical diseases originate in defective genes on specific chromosomes. In Golden Retrievers, Progressive Retinal Atrophy (PRA) is a well-known problem – an eye disease that leads to blindness.

German Shepherds are frequently affected by hip dysplasia. Dalmatians can inherit a predisposition to deafness. Bernese Mountain Dogs have an increased risk of certain types of cancer.

For many of these diseases, genetic tests are available today. A breeder can check before mating whether their dogs carry problematic genes.

How do I recognise a responsible breeder?

A reputable breeder will show you the health certificates of the parent animals without being asked. These include X-rays of the hips, eye examinations, and genetic tests for breed-typical hereditary diseases.

Ask specifically: “Which genetic tests have you carried out on the parents?” A good breeder will gladly explain which chromosome-based diseases occur in their breed and how they prevent them.

What do chromosomal anomalies mean?

Sometimes errors occur during cell division. A puppy may then have too many or too few chromosomes. Such anomalies often lead to infertility, developmental disorders, or other health problems.

If chromosomal disorders are suspected, your vet can order a chromosome analysis. This is rarely necessary and mainly used for breeding dogs that are unexpectedly infertile.

Can genetic tests rule out all hereditary diseases?

No. Genetic tests only cover known mutations. Some hereditary diseases are influenced by multiple genes simultaneously or have not yet been fully researched.

New mutations also arise continuously. A genetically unremarkable dog can still become ill – the risk is just significantly lower.

Why is genetic diversity important?

The more closely related the parent animals are, the more similar their sets of chromosomes. This increases the likelihood that harmful genes occur in double copies and trigger diseases.

Good breeders avoid excessive inbreeding and ensure a broad genetic base. For rare breeds, this is a particular challenge because only few breeding animals are available.