In 1604, Felipe Monje Merino arrived in the New World with dreams of conquest but eventually settled in Cartago, Costa Rica, marrying Francisca López and having two children. Six generations later, three descendants with the surname Monge experienced late-onset deafness, despite being born with normal hearing. This deafness, starting with low-frequency loss, is caused by a dominant genetic mutation resulting from a single-letter change in a gene called human diaphanous 1, which regulates the actin cytoskeleton of hair cells in the organ of Corti, responsible for sensing sound vibrations. The book recounts the search for this mutation and its discovery, achieved through collaboration between the Monge family and scientists from Costa Rica and the USA.
In 1604, conqueror Felipe Monje Merino arrived in the New World seeking the prevailing American dream, but after repeated military failures settled in Cartago, Costa Rica, marrying Francisca López with whom he procreated two children. It is not known whether either was deaf, but we know for certain that six generation later three descendants bearing his surname (now changed to Monge) became deaf, after being born with normal audition. Late onset deafness in this family, that begins with low frequency loss, is a dominant genetic mutation that results from a single base mutation, a change of a G for a T.
This book describes the hunt for the mutation that causes deafness, and the discovery of this single-letter change that affects a gene named human diaphanous 1. Diaphanous is one of three similar genes that help regulate the actin cytoskeleton of the hair cells in the organ of Corti, the actual sensors for sound vibrations. The research was the result of a sustained collaboration of the Monge family with many scientists from Costa Rica and the USA
Figures ......................................................................................................... 11
Preface and acknowledgements ......................................................... 13
Chapter I. A grand old family ................................................................ 15
1.1. Deafness in the Monge family ...................................... 15
1.2. How to grow a family tree ............................................ 18
1.3. How the research began ............................................. 22
1.4. Searching for the common ancestor ............................ 30
1.5. Cartago in colonial days .............................................. 34
1.6. A Gift from Kansas ...................................................... 38
1.7. The Monge family deafness may be unique ................. 40
1.8. Where do names come from? ..................................... 41
1.9. Family heroes… .......................................................... 42
1.10. Social Consequences of the Hearing Loss ................ 45
Chapter 2. The power of language .................................................... 47
2.1. Spiral of hearing loss ................................................... 47
2.2. The Sound of Silence .................................................. 49
2.3. Following a sound wave .............................................. 51
2.4. The Evolution of the Human Ear .................................. 60
10 Journey into silence
2.5. The Long Trip to the Cerebral Cortex ........................... 64
2.6. The Gift of Human Language ....................................... 68
Chapter 3. The genetic history of the family .................................. 75
3.1. A Short Story of Genes ................................................ 75
3.2. Gene mapping the classical way ................................. 84
3.3. The road to Berkeley and Mary-Claire .......................... 88
3.4. Then came Jetty, Jan and Eric ..................................... 93
3.5. A walk up Parnassus Avenue .................................... 100
3.6. Eric catches a fly gene ............................................... 104
3.7. Splicing out of the box ............................................... 107
3.8. An unplanned experiment .......................................... 110
3.9. Surfing the Web ........................................................ 113
Chapter 4. Thou shalt never cease from exploration… ................ 121
4.1. What did we learn? ................................................... 121
4.2. Family reactions ........................................................ 124
4.3. To sign or not to sign: the right to choose .................. 126
4.4. The Road from Genetics to Ethics ............................. 133
4.5. Waiting for the Golden Age ........................................ 137
References ............................................................................................... 143
Literature cited ..................................................................................... 153
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