Doodle Generations Explained: F1, F1B, F2 and Multigen

Doodle generations describe a dog's family tree. An F1 is a first cross between a Poodle and another breed, such as a Golden Retriever or Labrador. An F1B is an F1 crossed back to a Poodle. An F2 has two F1 parents, and a multigen doodle comes from doodle-to-doodle breeding over several generations. Each step shifts the odds of a curly, furnished, lower-shedding coat, but the label is only shorthand: the genes each parent actually carries decide what the puppies get.

The short version

• F1 is the first cross: a Poodle and another breed, so about half Poodle.
• Each "B" is a cross back to a Poodle. An F1B is about three-quarters Poodle, an F1BB about seven-eighths.
• F2 and later generations reshuffle the genes, so one litter can range from curly to straight.
• Three genes shape most of the coat: one for furnishings (the beard and eyebrows), one for curl and one for coat length.
• Improper coats (no furnishings) don't appear in F1 or F1B litters from a typical Poodle, but can in F2, reverse-cross and some multigen litters.
• Tested parents beat labels. Two dogs called "F1B" can carry different genes.

What the letters and numbers mean

The F stands for "filial", a genetics term for a generation of offspring. The number counts generations of doodle-to-doodle breeding, and each B marks a backcross to a Poodle.

Some breeders also cross an F1 back to the other parent breed, for example an F1 Goldendoodle to a Golden Retriever. That puppy is only about a quarter Poodle, and it's the cross most likely to produce improper coats.

The three genes behind a doodle's coat

A study of more than 1,000 dogs from 80 breeds found that variants in three genes account for most coat types in purebred dogs. Doodle generations are really about how these three get passed down:

• Furnishings (RSPO2): the beard, eyebrows and moustache behind the teddy-bear face. One copy is enough to show. Most Poodles carry two copies, while Golden Retrievers, Labradors, Bernese Mountain Dogs, Cocker Spaniels and Cavaliers usually carry none.
• Curl (KRT71): one copy usually gives a wavy coat and two copies a curly one. Poodles carry two; most of the other parent breeds carry none.
• Length (FGF5): the long-coat version is recessive, so a dog needs two copies to grow a long coat. Poodles, Golden Retrievers, Bernese Mountain Dogs, Cavaliers and Cocker Spaniels have long coats, but Labradors usually carry the short-coat version, one reason Labradoodle coats vary so much.

Shedding follows the same genes. A 2016 study of more than 4,200 dogs linked shedding to the furnishings gene and to a fourth gene, MC5R, and found that low-shedding breeds such as the Poodle carry two copies of the furnishings variant. Our traits guides cover each of these genes in more depth.

Generation by generation: furnishings

These are the expected odds when the non-Poodle breed has no furnishings and the Poodle carries two copies.

Generation by generation: curl

Curl works differently, because one copy and two copies look different. The same assumptions apply: the non-Poodle breed has no curl and the Poodle carries two copies.

So the F1B's reputation for a curlier, lower-shedding coat holds up on average: every puppy gets furnishings and half get two curl copies. The catch is the word "average".

Why the label isn't a guarantee

• The odds assume typical parents. If a Poodle carries a hidden non-furnished copy, or a multigen parent carries genes nobody tested, the odds above change.
• A generation names the parents, not the genes. Two F1B littermates can inherit different curl genes and end up with different coats.
• The names aren't regulated. One breeder's "multigen" can mean something different from another's.
• Other genes play a part. Shedding is also linked to MC5R, and whether a doodle has an undercoat depends on a separate region of the genome that a 2019 study linked to single and double coats.

Multigen doodles and tested parents

Multigen breeding gives breeders room to choose. A breeder can DNA test the parents for furnishings, curl and coat length and pair them so a litter can't include improper coats: if at least one parent carries two furnishings copies, every puppy gets at least one. Two parents that each carry only one copy will have, on average, one improper-coat puppy in four. Our guide to improper coats covers how that works.

Multigen lines can also end up mostly Poodle. A 2020 genetic study of the Australian Labradoodle, one of the best-known multigen doodles, found it is predominantly Poodle at the DNA level and enriched for variants linked to a Poodle-like coat.

How DNA hints at a doodle's generation

A DNA test can't read a pedigree, but breed ancestry is a strong hint. An F1 usually comes back close to half Poodle and half the other breed, an F1B around three-quarters Poodle, and a multigen doodle can show three or more breeds. Because each parent passes on a random half of its DNA, real numbers wander: an F1B might land a little above or below three-quarters.

The PuppyGenes report pairs breed ancestry with a physical appearance section that predicts furnishings, curl, coat length and shedding, each where the sample supports it. Together they show what your doodle actually inherited, whatever its label says. Our example reports are both Poodle-dominant mixes with Labrador and Cocker Spaniel ancestry, and our guides to the Goldendoodle and Labradoodle walk through the generations for each cross.