4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs

Blue-eyed duo births hazel-eyed kid -- genetics or gossip fodder?

Dear Matthew Alice:

Now that my father has passed away, I "inherited" boxes that filled a basement, attic, and two-car garage (into which my father never put a car.) Amidst the papers, pictures, and assorted historic items there was a family tree going back into the late 17th Century. In a rare spare moment, I noted eye colour[CQ] beside each member. Virtually every male and female had blue eyes, except for me. Mine are hazel, though my mother assured me they were blue on my birth day[CQ two words] but "changed" sometime in the first year. My wife and all of her family also have blue eyes, as do our three children and all of our grandchildren. Recalling genetics taught in school, I thought that blue eye colour is a recessive gene, not allowing for other eye hues of descendants. Is it possible for me to have hazel eyes under those extraordinary circumstances? Have I discovered a family secret?

-- Buried in Boxes

If you're old enough to have grandchildren, be assured that everything you learned in biology class is now wrong. Time and science march on. One of the "facts" jettisoned by contemporary research is the assumption that only two genes predict eye color. Science guys are pretty sure there are genes they haven't even found yet that play some part in each person's ultimate peeper pigmentation. Though it might be an unusual occurrence, you (and millions of other kids) are testimony to the fact that two blue-eyed parents (or five blue-eyed generations) can produce a non-blue-eyed child. If we'd known this sooner, perhaps the divorce rate would be lower.

The main source of eye color is a layer of cells in the iris that contains deposits of pigment. The color we see is created by light entering the eye and being scattered by this layer. The size, shape, and density of these layered cells, plus the size and intensity of the pigment spots and their distribution within the cells determine the scatter pattern, and thus eye color and color depth. (Why is the sky blue? Same reason eyes are blue-- conditions that scatter blue light.) Gene patterns will influence the characteristics of this iris cell layer. How many genes? What's their influence? Stay tuned. Nobody's sure yet.

So far, eye science has identified three genes that are eye-pigment linked: green-blue, brown-blue, and brown. These will influence the amount of pigment (melanin) in the iris; at one extreme, dense deposits of melanin help make eyes look some shade of what we'd label "brown." At the other end of the continuum, minimal deposits create shades of "blue." And given a polygenic model for eye color, a family with predominantly blue-eyed ancestors can still carry a genetic potential for a brown- or hazel-eyed child. Actually, greenish eyes are colored by an additional pigment, lipochrome, so there's another viariable in the chromatic mix. Aren't you glad you took biology back when life was simpler?

Here's something you might be interested in.
Submit a free classified
or view all

Previous article

Superbloom lays claim to best café location in the city

On a patio overlooking Mission Bay, even boring mochas taste good
Next Article

San Diego – city of shame, University Avenue, roommates from hell, writers write about moms

Reader writers' favorite books, music, San Diego small towns, first day of school, the story I wanted to write but didn't

Dear Matthew Alice:

Now that my father has passed away, I "inherited" boxes that filled a basement, attic, and two-car garage (into which my father never put a car.) Amidst the papers, pictures, and assorted historic items there was a family tree going back into the late 17th Century. In a rare spare moment, I noted eye colour[CQ] beside each member. Virtually every male and female had blue eyes, except for me. Mine are hazel, though my mother assured me they were blue on my birth day[CQ two words] but "changed" sometime in the first year. My wife and all of her family also have blue eyes, as do our three children and all of our grandchildren. Recalling genetics taught in school, I thought that blue eye colour is a recessive gene, not allowing for other eye hues of descendants. Is it possible for me to have hazel eyes under those extraordinary circumstances? Have I discovered a family secret?

-- Buried in Boxes

If you're old enough to have grandchildren, be assured that everything you learned in biology class is now wrong. Time and science march on. One of the "facts" jettisoned by contemporary research is the assumption that only two genes predict eye color. Science guys are pretty sure there are genes they haven't even found yet that play some part in each person's ultimate peeper pigmentation. Though it might be an unusual occurrence, you (and millions of other kids) are testimony to the fact that two blue-eyed parents (or five blue-eyed generations) can produce a non-blue-eyed child. If we'd known this sooner, perhaps the divorce rate would be lower.

The main source of eye color is a layer of cells in the iris that contains deposits of pigment. The color we see is created by light entering the eye and being scattered by this layer. The size, shape, and density of these layered cells, plus the size and intensity of the pigment spots and their distribution within the cells determine the scatter pattern, and thus eye color and color depth. (Why is the sky blue? Same reason eyes are blue-- conditions that scatter blue light.) Gene patterns will influence the characteristics of this iris cell layer. How many genes? What's their influence? Stay tuned. Nobody's sure yet.

So far, eye science has identified three genes that are eye-pigment linked: green-blue, brown-blue, and brown. These will influence the amount of pigment (melanin) in the iris; at one extreme, dense deposits of melanin help make eyes look some shade of what we'd label "brown." At the other end of the continuum, minimal deposits create shades of "blue." And given a polygenic model for eye color, a family with predominantly blue-eyed ancestors can still carry a genetic potential for a brown- or hazel-eyed child. Actually, greenish eyes are colored by an additional pigment, lipochrome, so there's another viariable in the chromatic mix. Aren't you glad you took biology back when life was simpler?

Sponsored
Here's something you might be interested in.
Submit a free classified
or view all
Previous article

Wahoo send anglers to the ER

Their Hawaiian name, ‘ono’, means ‘delicious’
Next Article

Blue Line trolley to Nobel Drive to Poki One N Half

This is the start of a whole new way to see the county
Comments
0

Be the first to leave a comment.

Sign in to comment

Sign in

Ask a Hipster — Advice you didn't know you needed Big Screen — Movie commentary Blurt — Music's inside track Booze News — San Diego spirits Classical Music — Immortal beauty Classifieds — Free and easy Cover Stories — Front-page features Drinks All Around — Bartenders' drink recipes Excerpts — Literary and spiritual excerpts Feast! — Food & drink reviews Feature Stories — Local news & stories Fishing Report — What’s getting hooked from ship and shore From the Archives — Spotlight on the past Golden Dreams — Talk of the town Letters — Our inbox [email protected] — Local movie buffs share favorites Movie Reviews — Our critics' picks and pans Musician Interviews — Up close with local artists Neighborhood News from Stringers — Hyperlocal news News Ticker — News & politics Obermeyer — San Diego politics illustrated Outdoors — Weekly changes in flora and fauna Overheard in San Diego — Eavesdropping illustrated Poetry — The old and the new Reader Travel — Travel section built by travelers Reading — The hunt for intellectuals Roam-O-Rama — SoCal's best hiking/biking trails San Diego Beer — Inside San Diego suds SD on the QT — Almost factual news Sheep and Goats — Places of worship Special Issues — The best of Street Style — San Diego streets have style Surf Diego — Real stories from those braving the waves Tin Fork — Silver spoon alternative Under the Radar — Matt Potter's undercover work Unforgettable — Long-ago San Diego Unreal Estate — San Diego's priciest pads Your Week — Daily event picks
4S Ranch Allied Gardens Alpine Baja Balboa Park Bankers Hill Barrio Logan Bay Ho Bay Park Black Mountain Ranch Blossom Valley Bonita Bonsall Borrego Springs Boulevard Campo Cardiff-by-the-Sea Carlsbad Carmel Mountain Carmel Valley Chollas View Chula Vista City College City Heights Clairemont College Area Coronado CSU San Marcos Cuyamaca College Del Cerro Del Mar Descanso Downtown San Diego Eastlake East Village El Cajon Emerald Hills Encanto Encinitas Escondido Fallbrook Fletcher Hills Golden Hill Grant Hill Grantville Grossmont College Guatay Harbor Island Hillcrest Imperial Beach Imperial Valley Jacumba Jamacha-Lomita Jamul Julian Kearny Mesa Kensington La Jolla Lakeside La Mesa Lemon Grove Leucadia Liberty Station Lincoln Acres Lincoln Park Linda Vista Little Italy Logan Heights Mesa College Midway District MiraCosta College Miramar Miramar College Mira Mesa Mission Beach Mission Hills Mission Valley Mountain View Mount Hope Mount Laguna National City Nestor Normal Heights North Park Oak Park Ocean Beach Oceanside Old Town Otay Mesa Pacific Beach Pala Palomar College Palomar Mountain Paradise Hills Pauma Valley Pine Valley Point Loma Point Loma Nazarene Potrero Poway Rainbow Ramona Rancho Bernardo Rancho Penasquitos Rancho San Diego Rancho Santa Fe Rolando San Carlos San Marcos San Onofre Santa Ysabel Santee San Ysidro Scripps Ranch SDSU Serra Mesa Shelltown Shelter Island Sherman Heights Skyline Solana Beach Sorrento Valley Southcrest South Park Southwestern College Spring Valley Stockton Talmadge Temecula Tierrasanta Tijuana UCSD University City University Heights USD Valencia Park Valley Center Vista Warner Springs
Close