There are a few possibilities for what you might mean:
* Sex-linked traits: These are traits determined by genes located on the sex chromosomes (X and Y in humans). They are often called "X-linked" or "Y-linked" depending on which chromosome carries the gene.
* Linked traits: These are traits controlled by genes located on the same chromosome. Because these genes are physically close together, they tend to be inherited together, reducing the chance of them being separated during recombination.
* Multifactorial traits: These are traits that are influenced by multiple genes and environmental factors. Examples include height, weight, and susceptibility to certain diseases.
To give you a more specific answer, could you please provide more context? For example:
* Where did you encounter this term?
* What is the subject matter you're trying to understand?
* Can you give an example of a trait you believe to be "six-linked"?
Once I have more information, I can provide a more accurate and helpful answer.
