Coat colour inheritance in American mink (Neovison vison): Pedigree analysis

This work aims to establish a simplified genotype for American mink (Neovison vison), on the basis of a group of basic genes (Asip, Tyrp–1, Tyr, Myo–5a, and Mc–1r) and three modifying genes (fawn, Ednrb, and Kit). The analysis used pedigrees of 61 females of standard brown, palomino, and silverblue colour variations. The database covered 380 offspring in nine colour variations: brown, silverblue, palomino, brown cross, palomino cross, pearl, pastel, silverpastel, and white. The analysis led to a simplified genotype explaining the principles of inheritance of most common coat colour variations in Polish mink farms. Due to the limited number of animals and the limited number of colour variations used, the analysis could not test the inheritance of all colours found in mink. The genotype was constructed on the basis of the homologous genes responsible for coat colour found in most animal species.

Genetics of Orange, Red and Yellow Root Colours in Tropical Carrots (Dacus Carota L.)

The research was carried out to study the colour inheritance genetics of the root epidermis, core (phloem) and cortex (xylem), from the parental crosses of the varieties Pusa Meghali (Orange), Pusa Rudhira (Red) and Pusa Kulfi (Yellow). Resultant in crosses yielded uniform mixed colours in F1 (first filial generation), thus could enhance the security of human nutrition through the mixture of carotenoids and anthocyanins in the F1. The F1s were advance to produce F2 and backcross (BCP1 and BCP2) generations, and the Chi-square test ratio (χ2) showed that the root colour of the orange epidermis and cortex (xylem) was dominant over the red and yellow colours, and regulated by dominant genes Oe and Ocx from the parent Pusa Meghali. While, the root colour of the orange core (phloem) was found to be recessive to the red (Rc) from Pusa Rudhira and yellow (Yc) colour from Pusa Kulfi, and to be regulated by a single recessive gene (oc) from the parent Pusa Meghali. These finding of genetic inheritance of colours would be useful in the development of bio-fortified F1 hybrids and varieties which are rich in flavonoids.

Auto-sexing potential and growth performance in Rhode Island, Nigerian local chickens and their reciprocal crosses

This study was conducted to determine auto-sexing potential in Rhode Island, Nigerian local chicken and their reciprocal crosses. A total of 241 eggs were set in the incubator to determine the fertility, hatchability, % Hatch, % dead in shell, % dead in cell and % deformed chicks in the four genotypes (Rhode Island Red (RIR) x Rhode Island White (RIW), Rhode Island Red (RIR) x Rhode Island White (RIW), Nigerian Local Red (NLR) x Rhode Island White (RIW) and Nigerian Local Red (NLR) x Nigerian Local White (NLW). Only 94 eggs were hatched. RIRXRIW crossbred chicks had the highest percentage fertility of 88.89% followed by RIRxRIW (86.27%), NLRXRIW (77.36%) and NLRxNLW (72.31%), respectively. RIRxNLW had the highest percentage hatchability of 65.19%, followed by RIRxRIW (51.56%), NLRxNLW (51.06%) and NLRxRIW (24.39%). It was observed in the hatch-out analysis that the cross between NLRxRIW had the highest percentage of dead in shell (29.27%) followed by RIRxRIW (17.19%), NLRxNLW (17.02%) and RIRxNLW (11.36%), respectively. The highest percentage of dead in cell was recorded in NLRxRIW crossbred (43.33%), followed by NLRxNLW (31.92%), RIRxRIW (28.13%) and RIRxNLW (15.91%). The observed deformed chicks were highest in NLRxNLW (20.85%) followed by RIRxNLW (10.34%), RIRxRIW (6.06%) and NLRxNLW (0%), respectively. Also observed was the occurrence of bangers with NLRxRIW, having the highest occurrence of bangers (9.08%) and with NLRxNLW having no occurrence of bangers. The records of weekly body weight were taken on the 94 chicks and chi square analysis was used to test colour inheritance of chicks. Significant (P<0.05) difference was observed among genotypes in body weight of chicks at hatch and from weeks 1 to 8 weeks of age. The observed changes on body weight from 0 to 8th week of age of chicks showed significant difference across the four different genetic crossed groups (P<0.05) and weight at the 8th week showed that the cross between RIRxRIW (216.93g) had better in growth as compared to the cross between NLRxRIW (202.75g) and NLRxNLW (193.17g) which were statistically similar (P>0.05) and RIRxNLW (179.75g) crossbred chicks which had the lowest bodyweight at 8 weeks of age. The chi square (X2) analysis revealed that both RIRxRIW and NLRxRIW crossbred chicks were autosexed. The study concluded that selection for plumage colour showed great potential in determining the probability of chicks being autosexed. Also, pure bred of RIRXRIW and reciprocal cross of NLRXRIW showed great potential of producing autosexed chicks, while results on the direct crosses of NLRXNLW and RIRXNLW suggest that the pattern of inheritance of plumage colour is not simple. The study recommends further investigation to further ascertain the mode of plumage colour inheritance in the Nigerian Local Chickens.

Genetic background of coat colour in sheep

The coat colour of animals is an extremely important trait that affects their behaviour and is decisive for survival in the natural environment. In farm animal breeding, as a result of the selection of a certain coat colour type, animals are characterized by a much greater variety of coat types. This makes them an appropriate model in research in this field. A very important aspect of the coat colour types of farm animals is distinguishing between breeds and varieties based on this trait. Furthermore, for the sheep breeds which are kept for skins and wool, coat/skin colour is an important economic trait. Until now the study of coat colour inheritance in sheep proved the dominance of white colour over pigmented/black coat or skin and of black over brown. Due to the current knowledge of the molecular basis of ovine coat colour inheritance, there is no molecular test to distinguish coat colour types in sheep although some are available for other species, such as cattle, dogs, and horses. Understanding the genetic background of variation in one of the most important phenotypic traits in livestock would help to identify new genes which have a great effect on the coat colour type. Considering that coat colour variation is a crucial trait for discriminating between breeds (including sheep), it is important to broaden our knowledge of the genetic background of pigmentation. The results may be used in the future to determine the genetic pattern of a breed. Until now, identified candidate genes that have a significant impact on colour type in mammals mainly code for factors located in melanocytes. The proposed candidate genes code for the melanocortin 1 receptor (MC1R), agouti signaling protein (ASIP), tyrosinase-related protein 1 (TYRP1), microphthalmia-associated transcription factor MITF, and v-kit Hardy–Zuckerman 4 feline sarcoma viral oncogene homologue (KIT). However, there is still no conclusive evidence of established polymorphisms for specific coat colour types in sheep.