A young woman asks her mother, "Mom, how many kind of penises are there?"
The mother, surprised, answers, "Well, daughter, a man goes through three phases. In a man's twenties, a man's penis is like an oak, mighty and hard. In his thirties and forties, it is like a birch, flexible but reliable. After his fifties, it is like a Christmas tree."
"A Christmas tree?" the young woman asks.
"Yes, dried up and the balls are there for decoration only."
Alfred Henry SturtevantDied 5 Apr 1970 at age 78 (born 21 Nov 1891). American geneticist who developed (1913) a technique for mapping the location of specific genes of the chromosomes in the fruit fly Drosophila. Sturtevant's method for “chromosome mapping”, relies on the analysis of groups of linked genes. His paper, published in 1913, described the location of six sex-linked genes as deduced by the way in which they associate with each other: it is one of the classic papers in genetics. Sturtevant later discovered the so-called 'position effect', in which the expression of a gene depends on its position in relation to other genes. He also demonstrated that crossing over between chromosomes is prevented in regions where a part of the chromosome material is inserted the wrong way round. |
