The danger of being a recessive trait:
Once a hallmark of the boy and girl next door, blue eyes have become increasingly rare among American children. Immigration patterns, intermarriage, and genetics all play a part in their steady decline. While the drop-off has been a century in the making, the plunge in the past few decades has taken place at a remarkable rate.
About half of Americans born at the turn of the 20th century had blue eyes, according to a 2002 Loyola University study in Chicago. By mid-century that number had dropped to a third. Today only about one 1 of every 6 Americans has blue eyes, said Mark Grant, the epidemiologist who conducted the study.
A century ago, 80 percent of people married within their ethnic group, Grant said. Blue eyes -- a genetically recessive trait -- were routinely passed down, especially among people of English, Irish, and Northern European ancestry.
By mid-century, a person's level of education -- and not ethnicity -- became the primary factor in selecting a spouse. As intermarriage between ethnic groups became the norm, blue eyes began to disappear, replaced by brown.
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Ah, but as it goes on, we'll start seeing blue eyes showing up in dark faces ...
for a single locus recessive trait HW is
p^2 + 2pq + q^2. if frequency of blue eye genes (i believe the OCA locus in fact), the frequency of blue eye phenotype is q^2 assuming perfect dominance of brown eyes.
Aren't we disqualified for HW because of immigration?
Aren't we disqualified for HW because of immigration?
yeah, you're right, but is the rate of change of frequency enough to account for deviation for HW over this time?