Human Genes Closer To Dolphin's Than Any Land Animal
From Discovery Channel On-Line
For Years, Marine Biologists have told us that dolphins share many traits with humans, including intelligence and friendliness. Now, a comparison of dolphin and human chromosomes shows that the genetic make-up of dolphins is amazingly similar to humans.
In fact, researchers at Texas A&M University have found that dolphins have more in common with us genetically than cows, horses , or pigs.
"The extent of the genetic similarity came as a real suprise to us," say's David Busbee of Texas A&M University, who published his results in last week's Cytogenetics and Cell Genetics.
This information will not only help researchers construct the genetic blueprint of dolphins, but also bolster conservation efforts.
Aided by the progress in mapping the human genome, researchers will continue to identify individual genes on dolphin chromosomes. Busbee estimates it will save 20 years of work, and the similarities and differences will reveal how long ago dolphins and humans branched off the evolutionary tree.
Researchers at Texas A&M University applied "paints" or fluorescently labeled human chromosomes, and found that 13 of 22 dolphin chromosomes were exactly the same as human chromosomes.
Of the remaining nine dolphin chromosomes, many were combinations or rearrangements of their human counterparts. Researchers also identified three dolphin genes similar to human genes.
Until now, researchers have never been able to do genetic studies of dolphins because they are a protected species, making it difficult to get tissue from them. However, Busbee was able to grow colonies from cells when a female dolphin miscarried.
"Dolphins are marine mammals that swim in the ocean and it was astonishing to learn that we had more in common with the dolphin than with land mammals," says Horst Hameister, professor of medical genetics at the University of Ulm in Germany. In the past 15 years, the world's dolphin populations have dwindled conciderably, exacerbated by high levels of PCB's. Researchers speculate that PCB's impair the immune system of dolphins, leaving them vulnerable to disease.
"If we can show that humans are similar to dolphins, and anything that endangers dolphins is an equal concern for humans, it may be easier to persuade governments to become serious about combating industrial pollution and keeping oceans clean," says Busbee.
By Seema Kumar, Discovery Channel Online News. Copyright 1998 Discovery
Dolphin Swim Guidelines
* You are swimming in the ocean, not a pool. Be aware that conditions change (wind, waves, undertows, currents), sometimes very quickly. There can be creatures besides you and the cetaceans in the water. Be careful not to scrape yourself on the coral for your sake and the sake of the resource.
*Go lightly on the reef killing sunscreen. Cover up with wetsuits, rash guards etc. Use lotion, never oil.
*Periodically, look up out of the water to see where the shore is located. No kidding! It is very altering and fun to swim with dolphins. Before you know it you can be a couple of miles from shore!
*Swim with you hands resting lightly on your back, your arms at your side. Dolphins do not have arms. Reaching out to them can be considered aggressive by the dolphins. Be careful to not harrass the dolphins by grabbing at them. They will touch you if they want.
*If you are in a boating area put out a dive flag so that others know a swimmer is in the water.
*Allow the dolphins to set the pace. Swim with them. Give them plenty of space to make very wide turns.
*Be kind to other swimmers. Unfortunately, this has to be pointed out to some swimmers. No pushing, shoving, kicking or body slamming to get closer to dolphins please.
*Have fun! Dolphins are attracted to playfullness and joy. They may even bring you a leaf to play "catch and fetch". Laughter, singing, clapping, the dolphins appear to like.
*Do not overestimate your physical abilities. This is how swimmers get into trouble.
IF IN DOUBT, DO NOT GO OUT
ALL DOLPHINS ARE PROTECTED UNDER THE MARINE MAMMAL PROTECTION ACT!!
IT IS ILLEGAL TO HARRASS, HUNT, CAPTURE, COLLECT OR KILL ANY MARINE MAMMAL.
Every effort should be taken by boaters and swimmers to avoid chasing, encircling or dividing groups of dolphins.
Spinner dolphins are known to rest during the day, in shallow, protected coves. Increased care is required to avoid disturbing the dolphins.
Spinner Dolphins are nocturnal, they primarily feed at night and rest during the day. Fairly small and slender, they reach about 2 meters / 6 feet in length. They eat a variety of small fish and squid. Spinners have a dark dorsal cape, lighter gray band in the middle and a whitish belly. They are found only in the wild as they do not survive well in captivity. We call the above dolphin "quacker" as he always squeeks with delight as soon as he sees Ty, swimming over immediately. Then he cruises silenty along side for a time, quacking agian when he leaves. We recognize him by an irregular pectoral fin and a small hole directly below the dorsal fin on his lower belly. The pods we encounter usually number from 20 to 60 dolphins. When two or more pods combine, we can swim with 100 spinners at a time.
Bottlenose dolphins have a distictly stubby snout (rostrum), with a curved mouthline that looks like they are smiling. Thier backs range from dark to charcoal gray that fades to a lighter gray on their sides and bellies. Adult bottlenose in Hawaii can be almost 10 feet (over 3 meters) and weigh up to 600-800 pounds. The above sweetheart is a baby. We call him Sam. Bottlenose can be identified by scratches and scars. Bottlenose are the most likely to be found in captivity. Sam lives off the coast of Lanai. They feed by stunning their prey, tossing them them in the air with thier nose or flukes. They have been seen pushing thier prey onshore and temporarily beaching themselves to feed. Bottlenose have also been known to feed with groups of dolphins helping each other "fish" and sometimes even fisherman and dolphins work together! They are active during the day in both shallow and deep water. Bottlenose are usually found in smaller pods of 2-12.
Spotted Dolphins are born with virtually no spots. Babies look like the spinner dolphins except that thier dorsal fins are less triangular and are pointed at the tip. The amount of spots they will have depends on thier sex and age. There is some thought that adult males may have more spots than females. Spotted dolphins can be as big as 8.2 feet (2.5 meters) and are usually not found close to shore. Group sizes range from 20- 100 in Hawaii, much smaller in the Bahamas. They eat at night and during the day. They are very interactive with humans in the Bahamas with many one on one encounters.
