Locus - a specific place occupied by a gene on the chromosome.

Date: 2015-10-07; view: 667.

Alleles occurring in linkage group of the parent species, separate and form new combinations that fall into the gametes - a process called genetic recombination. Descendants obtained from these gametes are called recombinants or crossovers. The value of crossingover can be expressed as a percentage. One per cent of crossingover is the unit distance between genes.

The phenomenon of gene inheritance, restricting their free combination, is called a clutch of genes or linked inheritance (T. Morgan).

The exchange of identical segments of homologous chromosomes with the contained genes is called crossingover or chromosomes crossing.

Laboratory work №7

Consider the male Bonelli. It has a length of just a few millimeters. A larva is developing in the male by the random settling on the proboscis mature females. Further developing of the male penetrates the female sex organs, which leads a parasitic life. Its only function is the fertilization of eggs.

Total micropreparation, Magnifier

Male Boonellia viridis

Subject: Linked inheritance and crossingover. General statements of the inheritance chromosome theory. Genetical and cytological evidence of crossingover. The mechanism of crossingover. Unequal crossing over. Mitotic crossingover.

Objective: Studying of the main provisions of the chromosome theory of heredity. The solution of genetic problems.