ProblemAssume that long fingers are inherited as a recessive trait with 80% penetrance. Two people heterozygous for long fingers mate. What is the probability that their first child will have long fingers?L= short fingersl= long fingersL(short) >l (long)Ll X Ll short short gametes: ½ L ½ l ½ L ½ l fertilization: ½ L ½ l ½ L ¼ LL¼ Llshort short ½ l¼ Ll¼ ll short long

The probability that their first child will have long fingers is 20%  

Explanation:

Available data:

Cross) Two people heterozygous for long fingers mate

                            Ll          x         Ll

Gametes)    1/2 L    1/2l         1/2L    1/2l

Punnet Square)  

                               L         l

                     L      LL      Ll

                       l     Ll       ll

F1) 25% or 1/4 LL

     50% or 1/2 Ll

     25% or 1/4 ll

Long fingers are inherited with 80% penetrance, which means that 80% is the proportion of the population that expresses the phenotype long fingers. Hence, the probability that the first child in this cross will have long fingers is:

100% 80%

25% X = 20%  

i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.