Does a big baby savannah determine size in adulthood

[sacred]

As long as we all remember that the only percentage that is certain is that a F1 with the parents being a Serval and a cat without any Serval is 50%. All other numbers are guesstimates. So, in some sense, all the other percentages are marketing numbers.

It is possible for a F2 to be anywhere from 0% to 50% Serval if bred from a 50% F1 and a 0% Serval cat. In practice 0 and 50 never happen as the number of genes are so high.

In reality such is the nature of crossover that you could easily be getting 33% or 66% serval in an F1. Genetics is intentionally random like that.

 

[Chris Elliott]

In reality such is the nature of crossover that you could easily be getting 33% or 66% serval in an F1. Genetics is intentionally random like that.

In my scenario, where one parent of a F1 is a Serval and the other has no Serval, then exactly half of the genes came from the Serval, thus, exactly 50% Serval.

 

[sacred]

In my scenario, where one parent of a F1 is a Serval and the other has no Serval, then exactly half of the genes came from the Serval, thus, exactly 50% Serval.

I agree with your math on paper. I'm simply expanding your idea and suggesting that in reality nearly all of the offspring will - genetically - be above or below the 50% number depending on what percent of the total set of disparate genes (carving out the very wide set of redundant homologues) is inherited from the serval/domesticated cat as a function of random chromosomal crossover. There's probably a maternal/paternal line that "hard codes" certain sets of genes as well, but as there is no known genetic analysis of an F1 Savannah cat we can't really say. Thus, some kittens in the litter may be 46% serval as calculated by disparate genetics and some may be 52% and others 58% and others 42% etc.

 

[The Kasbah]

I was wondering if the physical size of the kittens within a litter determine their size as adults.Many breeders like to mention that a particular kitten is bigger than the litter mates ,with the assumption that it will be bigger as an adult.Is this mostly true in your experiences?

No, this is NOT true in my experience. We as Breeders can provide "guesstimates" as to the adult size of an infant, but it is only a GUESS and never a guarantee, despite what many websites claim. This is nothing more than a marketing ploy.

I had a litter of F2B kittens years ago with two males. One was massive and the brother was clearly the runt of the litter. Both were sold to pet homes and the owners followed up with us a year later to report on development. The massive boy had grown to a very respectable 17-pounds. Nothing could have prepared me for the update on our runt, however....he had exploded into a 28-pound giant of a boy!

The only way to guarantee yourself a large adult...it to purchase an ADULT.

 

[The Kasbah]

That do you think about % serval within a generation?Some breeders charge a premium for a higher percentage cat within a specific generation,mostly F1s and F2s.Again ,with the assumption that a higher % cat will be bigger and more serval like?It this marketing also?

I do agree that at the F1 Level, crossing to an F1 or F2 produces a HP F1 kitten. (62.5% or greater) I also agree that it is accurate to describe this F1 Mother as HP...but NOT her F2 kittens! There, in my opinion, IS no such thing as a HP F2, F3, etc...because there is no way to verify the genetics past the F1 level. I myself have a few HP F1 girls in my program. I may comment that the mother of an F2 litter is a HP F1, but I NEVER err in categorizing the F2 kittens as HP...

Using HP to describe anything other than an F1 is, once again, a marketing ploy to make the buyer believe he/she is getting something superior, which in most cases they are not. I have seen PLENTY of traditionally bred 50% F1s that look BETTER than many of the HP F1 kittens being produced today.

There are excellent questions, btw.

 

[Chris Elliott]

I agree with your math on paper. I'm simply expanding your idea and suggesting that in reality nearly all of the offspring will - genetically - be above or below the 50% number depending on what percent of the total set of disparate genes (carving out the very wide set of redundant homologues) is inherited from the serval/domesticated cat as a function of random chromosomal crossover.

I agree Servals and house cats share many of the same genes, and, thus, most genes are homologous and their alleles are also mostly shared. And, since Servals have, to the best of my knowledge, never been sequenced, we have no idea which are homologous, which alleles of homologous genes are shared, and which genes are unique to each species.

All we can really say at this point is that a F1 from a Serval and a house cat will have 19 chromosomes from the Serval and 19 from the house cat. That's the 50% I'm referring to.

If you refer to percentage of genes, then most F1 males will have fewer genes from the Serval father (obviously for most F1s the serval is the father) because the inherited Y chromosome is shorter and has less genes in it than the X chromosome inherited from the house cat mother. However, as I understand it, the expression of genes on the Y chromosome are not mitigated for the most part by genes on the X chromosome and thus are mostly expressed, so a male F1 may have a phenotype that is more "Servally".

Once you go beyond F1, or with a HP F1, you can no longer say with any certainty what the percentage is because of random chromosomal crossover.

Of course, now we understand that there is much more to genetics than chromosomes and associated DNA. There's mitochondrial DNA, which is only inherited from the mother, making most F1s even less Serval. Eggs and sperm also carry RNA--but less in sperm. This RNA, epigenetics, environment, dominance of genes in all of it's complexity, and other influences affect gene expression. So a F1 could have many Serval genes that aren't expressed, but could still be inherited by offspring.

There's probably a maternal/paternal line that "hard codes" certain sets of genes as well, but as there is no known genetic analysis of an F1 Savannah cat we can't really say. Thus, some kittens in the litter may be 46% serval as calculated by disparate genetics and some may be 52% and others 58% and others 42% etc.

As we can't calculate disparate genetics, I'll stick to 50% of chromosomes for this particular F1 mix is all we can definitively say.

Ziggy's breeder is a geneticist and we've had a few discussions on this topic. However, I'm an amateur at best and all mistakes are mine.

 

[sacred]

I agree Servals and house cats share many of the same genes, and, thus, most genes are homologous and their alleles are also mostly shared. And, since Servals have, to the best of my knowledge, never been sequenced, we have no idea which are homologous, which alleles of homologous genes are shared, and which genes are unique to each species.

All we can really say at this point is that a F1 from a Serval and a house cat will have 19 chromosomes from the Serval and 19 from the house cat. That's the 50% I'm referring to.

If you refer to percentage of genes, then most F1 males will have fewer genes from the Serval father (obviously for most F1s the serval is the father) because the inherited Y chromosome is shorter and has less genes in it than the X chromosome inherited from the house cat mother. However, as I understand it, the expression of genes on the Y chromosome are not mitigated for the most part by genes on the X chromosome and thus are mostly expressed, so a male F1 may have a phenotype that is more "Servally".

Once you go beyond F1, or with a HP F1, you can no longer say with any certainty what the percentage is because of random chromosomal crossover.

Of course, now we understand that there is much more to genetics than chromosomes and associated DNA. There's mitochondrial DNA, which is only inherited from the mother, making most F1s even less Serval. Eggs and sperm also carry RNA--but less in sperm. This RNA, epigenetics, environment, dominance of genes in all of it's complexity, and other influences affect gene expression. So a F1 could have many Serval genes that aren't expressed, but could still be inherited by offspring.



As we can't calculate disparate genetics, I'll stick to 50% of chromosomes for this particular F1 mix is all we can definitively say.

Ziggy's breeder is a geneticist and we've had a few discussions on this topic. However, I'm an amateur at best and all mistakes are mine.

Astute writeup. Only thing I will add is that while the chromosome number is (almost certainly) 50/50, certain things are going to be dominant and certain genes are going to be expressed so that you don't really have a 50% animal in front of you. You might have 50/50 DNA (sans the additional data on X chromosome) but depending on what happens during cross over for each kitten for the non-homologous genes, the dominant/recessive and heterozygous traits are going to lean one way or another on a kitten by kitten basis. Certain traits are also likely to be always dominant or always recessive in the chimeric offspring as well.

 

[Gas doc]

Very interesting discussion,I wish I payed more attention in my genetics class in Med School,lol.
I have another question regarding the labeling of the hybrid offspring.Some breeders call them "cubs",while others call them "kittens".Is this marketing also?Is a F1 or maybe F2 technically considered a kitten or a cubb?

 

[The Kasbah]

Very interesting discussion,I wish I payed more attention in my genetics class in Med School,lol.
I have another question regarding the labeling of the hybrid offspring.Some breeders call them "cubs",while others call them "kittens".Is this marketing also?Can a F1 or maybe F2 be technically considered a kitten or a cubb?

ALL Savannahs (regardless of generation) are KITTENS. PERIOD. Servals have cubs. Lions, tigers and bears have cubs. Savannahs have kittens! To answer your question, the use of CUBS to describe Savannahs IS marketing...at it's WORST, I might add!

 

[sacred]

ALL Savannahs (regardless of generation) are KITTENS. PERIOD. Servals have cubs. Lions, tigers and bears have cubs. Savannahs have kittens! To answer your question, the use of CUBS to describe Savannahs IS marketing...at it's WORST, I might add!

Yep. Doesn't help with the (sometimes ignorant) public perception and bans to call them cubs.