Intestate Distribution to Ancestors and Collateral Relatives
If a decedent is survived by a spouse or issue, then all the decedent's intestate property goes to the surviving spouse or surviving issue, which includes children, grandchildren, and so on—nothing goes to the decedent's ancestors or to their issue, which includes brothers and sisters.
However, if the decedent had no surviving spouse or issue, then his estate goes to his ascendants, who are either ancestors or collateral relatives. Ancestors are progenitors of the decedent; hence, the decedent is the issue of all his ancestors. Collateral relatives (aka collateral kindred), or just collaterals, are all the issue of the decedent's ancestors that are not in the direct line of descent. So, parents and grandparents are ancestors while brothers and sisters, uncles and aunts, and cousins are collaterals.
Collateral relatives are further classified according to the degree of relationship to the decedent. First-line collaterals are the issue of the decedent's parents, who are the brothers and sisters of the decedent. Second-line collaterals are the issue of the grandparents not including the parents, which includes uncles and aunts, and first cousins. Likewise, third-line collaterals are the issue of great-grandparents not including grandparents and parents, and so on.
As with the distribution to issue, the 1st in line to inherit are the surviving ascendants who are more closely related to the decedent. And as with intestate distribution to issue, there are 3 main schemes for the intestate distribution to ascendants: degree of relationship approach, parentelic approach, or the degree of relationship with a parentelic tie-breaker.
Degree of Relationship Approach
Under the degree of relationship approach, the nearest kin of the decedent inherits. The degree of relationship is determined by counting the number of generations along the decedent's bloodline to those common ancestors that have surviving issue, then counting the generations from the ancestors to their surviving issue. All relatives with the lowest count inherit to the exclusion of all others.
In the parentelic approach, it is the degree of relationship to the nearest common ancestor that determines who inherits. Under this system, a relative who had a more closely related common ancestor than another would inherit, even if other relatives would be more closely related under the degree of relationship approach. Many states also use the per stirpes/per capita with representation/per capita at each generation intestate distribution schemes within the parentelic lines that have live takers.
Degree of Relationship with a Parentelic Tie-Breaker Approach
Some states use the degree of relationship approach with a parentelic tie-breaker, which considers the degree of relationship first and if there is more than 1 taker, then the parentelic approach is used to further narrow the number of relatives who would inherit. Relatives who have the same degree of relationship and the same parentelic relationship would inherit to the exclusion of all others.
When a parent has had children with more than 1 spouse, then the children will have brothers and sisters who share only 1 parent—hence, the term half-blood—half-brothers and half-sisters.
Under common law, only full-blooded siblings or their issue were entitled to inherit. However, under the UPC and in most states, half-bloods are now treated equally, except in a few jurisdictions where half-bloods' share of the estate is less than that of a full-blooded relative or half-bloods take only if there are no full-blooded takers.
Escheat to the State
Note that by going far enough up the family tree, there will be many people related to the decedent. Indeed, there have been many reclusive people who have died, only to have many people claiming to be their heirs. Sometimes they numbered in the thousands! Remotely related relatives were sometimes referred to as laughing heirs, since they had no emotional attachment to the decedent, and they were imagined to laugh all the way to the bank, elated by their good fortune.
Eventually the states got wise. All states now limit the degree of relationship in their intestate distribution laws. If there are no heirs related closely enough to satisfy the legal requirement, then the estate escheats to the state. This also greatly reduced fraud and the litigation of will challenges.
However, very few wealthy estates escheat to the state, since nothing attracts relatives like money.